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+# 存储运行时架构与边界说明
+
+## 📋 文档目的
+
+本文档用于说明当前仓库在 **Web / Extension / Desktop** 三种运行环境下的真实存储结构，重点回答以下问题：
+
+- 现在有哪些存储方式
+- 各存储里有哪些逻辑区域
+- 不同类型的内容会落到哪里
+- 每个区域的大小限制、配额和清理策略是什么
+- 当前已经建立了哪些防线
+- 还存在哪些灰区和后续必须补齐的边界
+
+本文档描述的是 **当前运行态事实**，不是理想设计图。
+
+## 🎯 核心原则
+
+当前系统必须严格区分两类数据：
+
+1. **结构化业务数据**
+   - 例如设置、会话快照、模型配置、收藏文本、上下文文档。
+   - 应存入结构化主存储。
+
+2. **图片二进制资产**
+   - 例如上传图、生成图、收藏封面、收藏示例图。
+   - 必须存入独立图片资产库。
+   - 结构化主存储中只允许保存图片引用和轻量元数据，不允许保存大体积 inline base64。
+
+这条边界是本轮存储事故复盘后的第一原则。
+
+## 🧱 一、物理存储介质
+
+### 1. Web / Extension 结构化主存储
+
+- 介质：IndexedDB
+- 实现：`DexieStorageProvider`
+- 数据库名：`PromptOptimizerDB`
+- 表结构：单表 `storage`
+- 本质：一个共享的 KV 桶
+
+相关文件：
+
+- `packages/core/src/services/storage/dexieStorageProvider.ts`
+
+### 2. Desktop 结构化主存储
+
+- 介质：主进程 JSON 文件
+- 实现：`FileStorageProvider`
+- 主文件：`<userData>/prompt-optimizer-data.json`
+- 备份文件：`<userData>/prompt-optimizer-data.json.backup`
+- 写入方式：内存镜像 + 延迟写盘 + 原子替换 + 备份恢复
+
+相关文件：
+
+- `packages/core/src/services/storage/fileStorageProvider.ts`
+- `packages/desktop/main.js`
+
+### 3. Session 图片资产库
+
+- 介质：IndexedDB
+- 实现：`ImageStorageService`
+- 数据库名：`PromptOptimizerImageDB`
+- 目标：保存会话使用的上传图、生成图和相关图片资产
+
+表结构分为两张表：
+
+- `imageMetadata`
+- `imageData`
+
+相关文件：
+
+- `packages/core/src/services/image/storage.ts`
+- `packages/ui/src/composables/system/useAppInitializer.ts`
+
+### 4. Favorite 图片资产库
+
+- 介质：IndexedDB
+- 实现：`ImageStorageService`
+- 数据库名：`PromptOptimizerFavoriteImageDB`
+- 目标：保存收藏项相关的封面图、示例图、引用图资产
+
+表结构同样分为两张表：
+
+- `imageMetadata`
+- `imageData`
+
+相关文件：
+
+- `packages/core/src/services/image/storage.ts`
+- `packages/ui/src/composables/system/useAppInitializer.ts`
+
+### 5. 非主线路径 provider
+
+代码里还存在两个 provider，但不是当前线上主路径：
+
+- `LocalStorageProvider`
+  - 浏览器本地存储实现
+  - 代码声明能力上限约 `5MB`
+- `MemoryStorageProvider`
+  - 主要用于测试或临时环境
+
+相关文件：
+
+- `packages/core/src/services/storage/localStorageProvider.ts`
+- `packages/core/src/services/storage/factory.ts`
+
+## 🗂️ 二、结构化主存储里的逻辑分区
+
+虽然 Web 物理上只有 `PromptOptimizerDB.storage` 一张表，Desktop 物理上只有一个 JSON 文件，但逻辑上可以拆成以下几块。
+
+### 1. `pref:*` 命名空间
+
+由 `PreferenceService` 统一管理。逻辑 key 会被自动加上 `pref:` 前缀后再落盘。
+
+示例：
+
+- `global-settings/v1` -> `pref:global-settings/v1`
+- `session/v1/basic-system` -> `pref:session/v1/basic-system`
+- `variableManager.storage` -> `pref:variableManager.storage`
+
+相关文件：
+
+- `packages/core/src/services/preference/service.ts`
+
+### 2. Core 直接 key
+
+这些 key 不经过 `PreferenceService`，直接写入主存储：
+
+- `models`
+- `image-models`
+- `user-templates`
+- `prompt_history`
+
+相关文件：
+
+- `packages/core/src/constants/storage-keys.ts`
+
+### 3. Context 单文档区
+
+上下文不是按多个 key 分散存，而是集中在一个文档里：
+
+- `ctx:store`
+
+这个文档同时保存：
+
+- 所有 context 数据
+- 当前激活的 context id
+- 文档版本号
+
+相关文件：
+
+- `packages/core/src/services/context/constants.ts`
+- `packages/core/src/services/context/repo.ts`
+
+### 4. Favorites 直接 key 区
+
+收藏系统也是独立 key，不经过 `PreferenceService`：
+
+- `favorites`
+- `favorite_categories`
+- `favorite_stats`
+- `favorite_tags`
+- `favorite_categories_initialized`
+
+相关文件：
+
+- `packages/core/src/services/favorite/manager.ts`
+
+### 5. 旧 UI key / 混合态 key
+
+当前仓库仍存在一批历史 key 和新快照并存的情况，包括但不限于：
+
+- `global-settings/v1`
+- `app:settings:ui:function-mode`
+- `app:settings:ui:basic-sub-mode`
+- `app:settings:ui:pro-sub-mode`
+- `app:settings:ui:builtin-template-language`
+
+需要特别注意：
+
+- `imageSubMode` 现在以路由为真源，不再直接依赖 preference 持久化
+- 但应用外壳仍会把当前路由状态镜像回 `global-settings/v1`
+
+相关文件：
+
+- `packages/ui/src/stores/settings/useGlobalSettings.ts`
+- `packages/ui/src/composables/mode/useFunctionMode.ts`
+- `packages/ui/src/composables/mode/useBasicSubMode.ts`
+- `packages/ui/src/composables/mode/useProSubMode.ts`
+- `packages/ui/src/composables/mode/useImageSubMode.ts`
+- `packages/ui/src/components/app-layout/PromptOptimizerApp.vue`
+
+## 📦 三、不同内容现在实际存到哪里
+
+### 1. 会话快照
+
+各功能区会话存储在 `pref:session/v1/*` 下，包括：
+
+- basic-system
+- basic-user
+- pro-multi
+- pro-variable
+- image-text2image
+- image-image2image
+- image-multiimage
+
+这些快照保存的是结构化 JSON，例如：
+
+- 原始 prompt
+- 优化后 prompt
+- 模型选择
+- 模板选择
+- 评测结果
+- 变量值
+- 图片引用 id
+
+相关文件：
+
+- `packages/ui/src/stores/session/useSessionManager.ts`
+- `packages/ui/src/stores/session/useBasicSystemSession.ts`
+- `packages/ui/src/stores/session/useBasicUserSession.ts`
+- `packages/ui/src/stores/session/useProMultiMessageSession.ts`
+- `packages/ui/src/stores/session/useProVariableSession.ts`
+- `packages/ui/src/stores/session/useImageText2ImageSession.ts`
+- `packages/ui/src/stores/session/useImageImage2ImageSession.ts`
+- `packages/ui/src/stores/session/useImageMultiImageSession.ts`
+
+### 2. Session 图片
+
+会话中真正的图片字节不应该放进 session 快照，而是写入 `PromptOptimizerImageDB`。
+
+session 快照里应该只保留：
+
+- `assetId`
+- `image-ref`
+- 轻量 metadata
+
+图片写入和引用转换相关文件：
+
+- `packages/ui/src/utils/image-asset-storage.ts`
+- `packages/ui/src/stores/session/imageStorageMaintenance.ts`
+
+### 3. 收藏文本和收藏元数据
+
+收藏项本体仍保存在结构化主存储中的 `favorites` key 下。
+
+其中包含：
+
+- 标题
+- 正文内容
+- 标签
+- 分类
+- functionMode
+- optimizationMode
+- imageSubMode
+- metadata
+
+注意：
+
+- `favorites` 不是 `pref:*` 命名空间的一部分
+- 因此它不受 `PreferenceService` 针对 session 的大小防线保护
+
+相关文件：
+
+- `packages/core/src/services/favorite/manager.ts`
+
+### 4. 收藏图片资产
+
+收藏相关图片应该写入 `PromptOptimizerFavoriteImageDB`，然后在收藏 metadata 中保存引用信息：
+
+- `coverAssetId`
+- `assetIds`
+- `imageAssetIds`
+- `inputImageAssetIds`
+
+相关文件：
+
+- `packages/ui/src/utils/favorite-media.ts`
+- `packages/ui/src/components/SaveFavoriteDialog.vue`
+- `packages/ui/src/composables/app/useAppPromptGardenImport.ts`
+
+### 5. 收藏图片 fallback
+
+当前收藏元数据 schema 仍允许 URL 型 fallback：
+
+- `coverUrl`
+- `urls`
+
+这意味着当前系统允许：
+
+- 远程 URL fallback
+
+但现在已经明确禁止：
+
+- `data:image/...;base64,...` 这种 inline 数据 URL 被写入 favorite metadata
+
+相关文件：
+
+- `packages/ui/src/utils/favorite-media.ts`
+- `packages/core/src/services/favorite/manager.ts`
+
+### 6. Prompt Garden 导入收藏
+
+Prompt Garden 导入链路已经改成严格模式：
+
+- 优先把图片落到图片资产库
+- 不再允许把 inline 图片内容回退进收藏 metadata
+- 自动收藏路径在图片落盘失败时会跳过收藏保存
+- 确认弹窗路径在图片落盘失败时不再附带 `media` fallback
+
+相关文件：
+
+- `packages/ui/src/composables/app/useAppPromptGardenImport.ts`
+
+### 7. 模型、模板、历史、上下文
+
+这几类数据都属于结构化主存储：
+
+- 模型配置 -> `models`
+- 图像模型配置 -> `image-models`
+- 用户模板 -> `user-templates`
+- 历史记录 -> `prompt_history`
+- 上下文文档 -> `ctx:store`
+
+相关文件：
+
+- `packages/core/src/services/model/manager.ts`
+- `packages/core/src/services/template/manager.ts`
+- `packages/core/src/services/history/manager.ts`
+- `packages/core/src/services/context/repo.ts`
+
+## 📏 四、大小限制、配额和清理策略
+
+### 1. Session 快照大小限制
+
+`PreferenceService` 现在对 `session/*` key 建立了硬限制：
+
+- 单条 session 快照最大 `1 MiB`
+
+限制覆盖：
+
+- 写入时校验
+- 读取时校验
+
+超限行为：
+
+- 写入失败，抛出结构化存储错误
+- 读取失败时，`SessionManager` 会清理超限的单个 session key，而不是清空整库
+
+相关文件：
+
+- `packages/core/src/services/preference/service.ts`
+- `packages/ui/src/stores/session/useSessionManager.ts`
+
+### 2. Session 图片库配额
+
+`PromptOptimizerImageDB` 默认配额：
+
+- `maxCacheSize = 50 MB`
+- `maxAge = 7 天`
+- `maxCount = 100`
+- `autoCleanupThreshold = 0.8`
+
+清理顺序：
+
+1. 清理过期图片
+2. 超过数量上限时按最旧访问时间删除
+3. 超过总容量时继续按最旧访问时间删除，直到降到目标阈值
+
+相关文件：
+
+- `packages/core/src/services/image/storage.ts`
+- `packages/ui/src/composables/system/useAppInitializer.ts`
+
+### 3. Favorite 图片库配额
+
+`PromptOptimizerFavoriteImageDB` 默认配额：
+
+- `maxCacheSize = 200 MB`
+- `maxAge = 365 天`
+- `maxCount = 1000`
+- `autoCleanupThreshold = 0.9`
+
+这套配置比 session 图片库更宽松，因为收藏被视为长期保留资产。
+
+相关文件：
+
+- `packages/core/src/services/image/storage.ts`
+- `packages/ui/src/composables/system/useAppInitializer.ts`
+
+### 4. 历史记录限制
+
+`prompt_history` 最多保留：
+
+- `50` 条记录
+
+相关文件：
+
+- `packages/core/src/services/history/manager.ts`
+
+### 5. Desktop 文件存储运行特性
+
+Desktop 主存储没有应用层固定大小上限，但有运行时写盘策略：
+
+- 延迟写入：`500ms`
+- 最大 flush 超时：`3s`
+- 自动备份恢复：主文件失败时尝试 backup
+
+这意味着 Desktop 不是“无限安全”，只是没有像 session 那样的显式 size cap。
+
+相关文件：
+
+- `packages/core/src/services/storage/fileStorageProvider.ts`
+
+### 6. LocalStorage provider 能力上限
+
+`LocalStorageProvider` 报告的能力上限约为：
+
+- `5MB`
+
+但它不是当前主线路径。
+
+相关文件：
+
+- `packages/core/src/services/storage/localStorageProvider.ts`
+
+## 🔄 五、导入导出边界
+
+当前 `DataManager.exportAllData()` 导出的不是整套运行态存储，而是一个经过裁剪的业务数据集合。
+
+当前导出包含：
+
+- `history`
+- `models`
+- `userTemplates`
+- `userSettings`
+- `contexts`
+
+当前不包含：
+
+- `favorites`
+- `favorite image assets`
+- `session snapshots`
+- `session image assets`
+
+因此必须明确：
+
+- **导入导出边界 != 运行时存储边界**
+- 当前导入导出不能视为完整灾备备份
+
+相关文件：
+
+- `packages/core/src/services/data/manager.ts`
+- `packages/core/src/services/preference/service.ts`
+
+## 🚨 六、当前已经建立的防线
+
+### 1. Session 超限防线
+
+- `session/*` 超过 `1 MiB` 直接拒绝
+- 恢复时只清理超限单 key，不再整库清空
+
+### 2. Favorite inline 图片防线
+
+- FavoriteManager 现在拒绝 `data:image/...` inline data URL 进入 metadata
+
+### 3. Prompt Garden 收藏严格落盘策略
+
+- 图片资产落盘失败时不再用 inline 图片兜底
+
+### 4. Session 图片与结构化快照分层
+
+- 图片二进制进入独立图片库
+- session 快照只保留引用
+
+## ⚠️ 七、当前仍存在的灰区和风险
+
+### 1. 结构化主存储物理上仍是共享桶
+
+无论在 Web 还是 Desktop，本质上都还是单一主存储容器：
+
+- Web 是一张 Dexie 表
+- Desktop 是一个 JSON 文件
+
+这意味着只要某条链路把大对象写错位置，影响范围就不是单个业务模块，而是整个主存储。
+
+### 2. Favorites 不经过 PreferenceService
+
+`favorites` 是直接 key，不走 `PreferenceService`，因此：
+
+- session 的 `1 MiB` 防线不覆盖 favorites
+- favorites 必须在自身 manager 和调用方建立独立边界
+
+### 3. Favorite 图片资产目前更像“配额库”，不是“强引用回收库”
+
+已确认：
+
+- session 图片库会根据 session 快照引用做 GC
+- 收藏删除链路当前只删除 `favorites` 文本记录
+- 没有看到收藏删除后同步清理 `PromptOptimizerFavoriteImageDB` 孤儿资产的强引用回收逻辑
+
+这意味着当前 favorite 图片库仍存在孤儿资产积累风险，更多依赖配额清理，而不是引用级删除。
+
+相关文件：
+
+- `packages/ui/src/stores/session/imageStorageMaintenance.ts`
+- `packages/ui/src/components/FavoriteButton.vue`
+- `packages/ui/src/components/FavoriteManager.vue`
+- `packages/core/src/services/favorite/manager.ts`
+
+### 4. UI 设置仍处于混合态
+
+当前存在：
+
+- 新的 `global-settings/v1`
+- 旧的 `app:settings:ui:*`
+- 路由真源与持久化镜像并存
+
+这不一定立即导致数据损坏，但会提高认知成本，也会增加后续修改时误写双真源的风险。
+
+### 5. 导出数据不覆盖图片资产
+
+当前导出文件不能还原：
+
+- 收藏图片库
+- session 图片库
+
+这也是为什么“运行时数据完整性”和“导出文件完整性”必须分开讨论。
+
+## 🛡️ 八、必须遵守的存储红线
+
+后续所有功能开发必须遵守以下规则：
+
+### 红线 1：结构化主存储禁止承载大体积二进制内容
+
+禁止把以下内容直接写入主存储：
+
+- 图片 base64
+- data URL
+- 大型二进制序列化字符串
+
+### 红线 2：图片只能进入图片资产库
+
+所有图片相关能力都必须遵循：
+
+- 先落图片资产库
+- 再把 `assetId` 写入业务对象
+
+### 红线 3：任何 fallback 都不能回退到 inline 图片
+
+允许的 fallback：
+
+- 外部 URL
+- 跳过保存
+- 显式失败
+
+禁止的 fallback：
+
+- 将 `data:image/...` 写回 favorites 或 session metadata
+
+### 红线 4：删除业务对象必须考虑资产回收
+
+如果一个对象持有图片 `assetId`，那么删除该对象时必须明确以下策略之一：
+
+- 立即删除资产
+- 标记引用减少后异步 GC
+- 周期性按引用扫描清理
+
+不能只删文本记录，不考虑资产生命周期。
+
+### 红线 5：provider 级测试必须覆盖真实请求体和真实落盘结果
+
+仅验证“调用链路经过某个 adapter”是不够的。
+
+必须补齐：
+
+- provider 级 payload 断言
+- 存储层实际写入结果断言
+- 大对象拒绝与回退行为断言
+
+## 🧭 九、建议的后续治理方向
+
+### 1. Favorite 图片库补引用级 GC
+
+目标：
+
+- 删除收藏时同步处理收藏图片资产
+- 或建立 favorites 专属的引用扫描 + 清理任务
+
+### 2. 为 favorites 建立独立 size guard
+
+建议：
+
+- 不依赖 `PreferenceService`
+- 在 `FavoriteManager` 或更底层 provider 边界增加单项和总量限制
+
+### 3. 收口 UI 设置双真源
+
+建议逐步统一：
+
+- 哪些由路由主导
+- 哪些由 `global-settings/v1` 主导
+- 哪些旧 key 只保留迁移读，不再写入
+
+### 4. 补齐“结构化存储禁止 inline 图片”的系统性测试
+
+建议至少覆盖：
+
+- session
+- favorites
+- Prompt Garden import
+- SaveFavoriteDialog
+- 未来任何带图片快照的新功能
+
+## ✅ 十、结论
+
+当前系统的真实运行时存储结构可以总结为：
+
+1. **结构化主存储**
+   - 保存设置、会话快照、模型、模板、历史、上下文、收藏文本等结构化数据。
+
+2. **Session 图片资产库**
+   - 保存会话期间使用的图片字节。
+
+3. **Favorite 图片资产库**
+   - 保存收藏相关的图片资产。
+
+当前已经建立了两条关键防线：
+
+- `session/*` 的 `1 MiB` 硬限制
+- favorites metadata 禁止 inline 图片 data URL
+
+但要彻底避免同类事故再次发生，还需要继续补齐：
+
+- favorite 图片资产回收
+- favorites 的独立容量防线
+- 旧 UI key 的收口
+- provider / storage 边界的强测试
+
+只有当“结构化数据”和“图片资产”在架构、代码、测试、删除回收四个层面都被强制分层后，这类问题才算真正从根上解决。
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 6145919f..2691c220 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -106,6 +106,16 @@ export { DexieStorageProvider } from './services/storage/dexieStorageProvider'
 export { LocalStorageProvider } from './services/storage/localStorageProvider'
 export { MemoryStorageProvider } from './services/storage/memoryStorageProvider'
 export { FileStorageProvider } from './services/storage/fileStorageProvider'
+export {
+  runStorageStartupSafetyCheck,
+  writeStartupRepairReport,
+  STARTUP_REPAIR_REPORT_PREFERENCE_KEY,
+  STARTUP_REPAIR_REPORT_STORAGE_KEY,
+} from './services/storage/startup-safety-check'
+export type {
+  StartupRepairAction,
+  StartupRepairReport,
+} from './services/storage/startup-safety-check'
 
 // 导出提示词服务相关
 export { PromptService } from './services/prompt/service'
@@ -208,6 +218,16 @@ export * from './services/context/constants'
 export { FavoriteManager } from './services/favorite/manager'
 export { FavoriteManagerElectronProxy } from './services/favorite/electron-proxy'
 export { TagTypeConverter } from './services/favorite/type-converter'
+export {
+  FAVORITE_ITEM_HARD_LIMIT_BYTES,
+  FAVORITES_SOFT_LIMIT_BYTES,
+  FAVORITES_HARD_LIMIT_BYTES,
+  INLINE_IMAGE_DATA_URL_RE,
+  assertFavoriteMetadataHasNoInlineImages,
+  assertFavoriteFitsItemBudget,
+  assertFavoritesPayloadWithinBudget,
+  normalizeFavoriteRecord,
+} from './services/favorite/storage-guards'
 export * from './services/favorite/types'
 export * from './services/favorite/errors'
 
diff --git a/packages/core/src/services/favorite/manager.ts b/packages/core/src/services/favorite/manager.ts
index 74f18fc6..c0f89e39 100644
--- a/packages/core/src/services/favorite/manager.ts
+++ b/packages/core/src/services/favorite/manager.ts
@@ -17,6 +17,11 @@ import {
 } from './errors';
 import { TypeMapper } from './type-mapper';
 import { TagTypeConverter } from './type-converter';
+import {
+  assertFavoriteFitsItemBudget,
+  assertFavoriteMetadataHasNoInlineImages,
+  assertFavoritesPayloadWithinBudget,
+} from './storage-guards';
 
 /**
  * 收藏管理器实现
@@ -209,6 +214,8 @@ export class FavoriteManager implements IFavoriteManager {
       }
     }
 
+    assertFavoriteMetadataHasNoInlineImages(favorite.metadata);
+
     const favoriteData = {
       title: favorite.title?.trim() || favorite.content.slice(0, 50) + (favorite.content.length > 50 ? '...' : ''),
       content: favorite.content,
@@ -231,13 +238,18 @@ export class FavoriteManager implements IFavoriteManager {
       updatedAt: now,
       useCount: 0
     };
+    assertFavoriteFitsItemBudget(newFavorite);
 
     try {
       await this.storageProvider.updateData(this.STORAGE_KEYS.FAVORITES, (favorites: FavoritePrompt[] | null) => {
         const favoritesList = favorites || [];
         // 🔧 移除重复内容检查 - 允许收藏相同内容但属性不同的提示词
         // 用户可能需要��同一内容设置不同的标题、分类、标签等
-        return [...favoritesList, newFavorite];
+        const nextFavoritesList = [...favoritesList, newFavorite];
+        assertFavoritesPayloadWithinBudget(nextFavoritesList, {
+          warnOnSoftLimit: true,
+        });
+        return nextFavoritesList;
       });
 
       await this.updateStats();
@@ -345,6 +357,10 @@ export class FavoriteManager implements IFavoriteManager {
     await this.ensureInitialized();
 
     try {
+      if (Object.prototype.hasOwnProperty.call(updates, 'metadata')) {
+        assertFavoriteMetadataHasNoInlineImages(updates.metadata);
+      }
+
       await this.storageProvider.updateData(this.STORAGE_KEYS.FAVORITES, (favorites: FavoritePrompt[] | null) => {
         const favoritesList = favorites || [];
         const index = favoritesList.findIndex(f => f.id === id);
@@ -352,11 +368,17 @@ export class FavoriteManager implements IFavoriteManager {
           throw new FavoriteNotFoundError(id);
         }
 
-        favoritesList[index] = {
+        const nextFavorite = {
           ...favoritesList[index],
           ...updates,
           updatedAt: Date.now()
         };
+        assertFavoriteFitsItemBudget(nextFavorite);
+
+        favoritesList[index] = nextFavorite;
+        assertFavoritesPayloadWithinBudget(favoritesList, {
+          warnOnSoftLimit: true,
+        });
 
         return favoritesList;
       });
@@ -1116,6 +1138,7 @@ export class FavoriteManager implements IFavoriteManager {
 
         const normalizeMetadata = (metadata: unknown) => {
           if (metadata && typeof metadata === 'object') {
+            assertFavoriteMetadataHasNoInlineImages(metadata);
             return metadata as Record<string, unknown>;
           }
           return undefined;
@@ -1197,6 +1220,7 @@ export class FavoriteManager implements IFavoriteManager {
               updatedAt,
               useCount
             };
+            assertFavoriteFitsItemBudget(newFavorite);
 
             favoritesList.push(newFavorite);
             timestampOffset++;
@@ -1207,6 +1231,10 @@ export class FavoriteManager implements IFavoriteManager {
           }
         });
 
+        assertFavoritesPayloadWithinBudget(favoritesList, {
+          warnOnSoftLimit: true,
+        });
+
         return favoritesList;
       });
 
diff --git a/packages/core/src/services/favorite/storage-guards.ts b/packages/core/src/services/favorite/storage-guards.ts
new file mode 100644
index 00000000..ab5b2562
--- /dev/null
+++ b/packages/core/src/services/favorite/storage-guards.ts
@@ -0,0 +1,235 @@
+import type { FavoritePrompt } from './types'
+import { FavoriteValidationError } from './errors'
+import { TypeMapper } from './type-mapper'
+
+const TEXT_ENCODER = new TextEncoder()
+
+export const INLINE_IMAGE_DATA_URL_RE = /^data:image\/[a-z0-9.+-]+(?:;charset=[^;,]+)?;base64,/iu
+
+export const FAVORITE_ITEM_HARD_LIMIT_BYTES = 512 * 1024
+export const FAVORITES_SOFT_LIMIT_BYTES = 2 * 1024 * 1024
+export const FAVORITES_HARD_LIMIT_BYTES = 8 * 1024 * 1024
+const FAVORITES_SOFT_WARNING_HEADROOM_BYTES = 8 * 1024
+
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+  !!value && typeof value === 'object' && !Array.isArray(value)
+
+const toTrimmedString = (value: unknown): string | undefined => {
+  if (typeof value !== 'string') return undefined
+  const trimmed = value.trim()
+  return trimmed ? trimmed : undefined
+}
+
+const parseTimestamp = (value: unknown, fallback: number): number => {
+  if (typeof value === 'number' && Number.isFinite(value) && value >= 0) {
+    return value
+  }
+
+  if (typeof value === 'string') {
+    const asNumber = Number(value)
+    if (Number.isFinite(asNumber) && asNumber >= 0) {
+      return asNumber
+    }
+
+    const asDate = Date.parse(value)
+    if (!Number.isNaN(asDate) && asDate >= 0) {
+      return asDate
+    }
+  }
+
+  return fallback
+}
+
+const normalizeTags = (value: unknown): string[] => {
+  if (!Array.isArray(value)) return []
+
+  return Array.from(
+    new Set(
+      value
+        .map((tag) => (typeof tag === 'string' ? tag.trim() : ''))
+        .filter(Boolean),
+    ),
+  )
+}
+
+export const getSerializedByteLength = (value: string): number =>
+  TEXT_ENCODER.encode(value).byteLength
+
+export const assertFavoriteMetadataHasNoInlineImages = (
+  value: unknown,
+  path = 'metadata',
+  seen: WeakSet<object> = new WeakSet(),
+): void => {
+  if (typeof value === 'string') {
+    if (INLINE_IMAGE_DATA_URL_RE.test(value.trim())) {
+      throw new FavoriteValidationError(
+        `Favorite metadata cannot contain inline image data URLs (${path})`,
+      )
+    }
+    return
+  }
+
+  if (!value || typeof value !== 'object') {
+    return
+  }
+
+  if (seen.has(value as object)) {
+    return
+  }
+  seen.add(value as object)
+
+  if (Array.isArray(value)) {
+    value.forEach((item, index) => {
+      assertFavoriteMetadataHasNoInlineImages(item, `${path}[${index}]`, seen)
+    })
+    return
+  }
+
+  Object.entries(value as Record<string, unknown>).forEach(([key, child]) => {
+    assertFavoriteMetadataHasNoInlineImages(child, `${path}.${key}`, seen)
+  })
+}
+
+export const assertFavoriteFitsItemBudget = (favorite: FavoritePrompt): number => {
+  const serializedFavorite = JSON.stringify(favorite)
+  const itemBytes = getSerializedByteLength(serializedFavorite)
+
+  if (itemBytes > FAVORITE_ITEM_HARD_LIMIT_BYTES) {
+    throw new FavoriteValidationError(
+      `Favorite entry exceeds hard limit of ${FAVORITE_ITEM_HARD_LIMIT_BYTES} bytes`,
+    )
+  }
+
+  return itemBytes
+}
+
+export const assertFavoritesPayloadWithinBudget = (
+  favorites: FavoritePrompt[],
+  options?: {
+    warnOnSoftLimit?: boolean
+    logWarning?: (message: string) => void
+  },
+): {
+  totalBytes: number
+  softLimitExceeded: boolean
+} => {
+  favorites.forEach((favorite) => {
+    assertFavoriteMetadataHasNoInlineImages(favorite.metadata)
+    assertFavoriteFitsItemBudget(favorite)
+  })
+
+  const totalBytes = getSerializedByteLength(JSON.stringify(favorites))
+  if (totalBytes > FAVORITES_HARD_LIMIT_BYTES) {
+    throw new FavoriteValidationError(
+      `favorites payload exceeds hard limit of ${FAVORITES_HARD_LIMIT_BYTES} bytes`,
+    )
+  }
+
+  const softLimitExceeded =
+    totalBytes > FAVORITES_SOFT_LIMIT_BYTES - FAVORITES_SOFT_WARNING_HEADROOM_BYTES
+  if (softLimitExceeded && options?.warnOnSoftLimit) {
+    const logWarning = options.logWarning ?? console.warn
+    logWarning(
+      `favorites payload exceeds soft limit (${totalBytes} bytes > ${FAVORITES_SOFT_LIMIT_BYTES} bytes)`,
+    )
+  }
+
+  return {
+    totalBytes,
+    softLimitExceeded,
+  }
+}
+
+export const normalizeFavoriteRecord = (
+  value: unknown,
+  fallbackTimestamp = Date.now(),
+): FavoritePrompt => {
+  if (!isPlainObject(value)) {
+    throw new FavoriteValidationError('Favorite entry must be an object')
+  }
+
+  const raw = value as Record<string, unknown>
+  const rawContent = typeof raw.content === 'string' ? raw.content : ''
+  if (!rawContent.trim()) {
+    throw new FavoriteValidationError('Favorite prompt content cannot be empty')
+  }
+
+  const content = rawContent
+  const metadata = isPlainObject(raw.metadata) ? { ...raw.metadata } : undefined
+  const originalContent = toTrimmedString(raw.originalContent)
+  const nextMetadata = originalContent
+    ? { ...(metadata || {}), originalContent }
+    : metadata
+
+  assertFavoriteMetadataHasNoInlineImages(nextMetadata)
+
+  let functionMode = raw.functionMode
+  let optimizationMode = raw.optimizationMode
+  const imageSubMode = raw.imageSubMode
+
+  if (
+    functionMode !== 'basic' &&
+    functionMode !== 'context' &&
+    functionMode !== 'image'
+  ) {
+    functionMode = 'basic'
+    optimizationMode = 'system'
+  }
+
+  if (
+    (functionMode === 'basic' || functionMode === 'context') &&
+    optimizationMode !== 'system' &&
+    optimizationMode !== 'user'
+  ) {
+    optimizationMode = 'system'
+  }
+
+  const mapping = {
+    functionMode,
+    optimizationMode,
+    imageSubMode,
+  }
+
+  if (!TypeMapper.validateMapping(mapping)) {
+    throw new FavoriteValidationError(
+      `Invalid favorite mode mapping: functionMode=${String(functionMode)}, optimizationMode=${String(optimizationMode)}, imageSubMode=${String(imageSubMode)}`,
+    )
+  }
+
+  const createdAt = parseTimestamp(raw.createdAt, fallbackTimestamp)
+  const updatedAt = parseTimestamp(raw.updatedAt, createdAt)
+  const title =
+    toTrimmedString(raw.title) ||
+    (content.length > 50 ? `${content.slice(0, 50)}...` : content)
+
+  const favorite: FavoritePrompt = {
+    id:
+      toTrimmedString(raw.id) ||
+      `fav_salvaged_${createdAt}_${Math.random().toString(36).slice(2, 11)}`,
+    title,
+    content,
+    description: typeof raw.description === 'string' ? raw.description : undefined,
+    createdAt,
+    updatedAt,
+    tags: normalizeTags(raw.tags),
+    category: toTrimmedString(raw.category),
+    useCount:
+      typeof raw.useCount === 'number' && Number.isFinite(raw.useCount) && raw.useCount >= 0
+        ? raw.useCount
+        : 0,
+    functionMode,
+    optimizationMode:
+      functionMode === 'basic' || functionMode === 'context'
+        ? (optimizationMode as 'system' | 'user')
+        : undefined,
+    imageSubMode:
+      functionMode === 'image'
+        ? (imageSubMode as 'text2image' | 'image2image' | 'multiimage')
+        : undefined,
+    metadata: nextMetadata,
+  }
+
+  assertFavoriteFitsItemBudget(favorite)
+
+  return favorite
+}
diff --git a/packages/core/src/services/image/storage.ts b/packages/core/src/services/image/storage.ts
index 68bc6a08..161735dc 100644
--- a/packages/core/src/services/image/storage.ts
+++ b/packages/core/src/services/image/storage.ts
@@ -251,8 +251,12 @@ export class ImageStorageService implements IImageStorageService {
    * @returns 清理的图像数量
    */
   async cleanupOldImages(): Promise<number> {
+    const maxAge = this.config.maxAge
+    if (typeof maxAge !== 'number' || !Number.isFinite(maxAge) || maxAge <= 0) {
+      return 0
+    }
+
     const now = Date.now()
-    const maxAge = this.config.maxAge!
     const cutoffTime = now - maxAge
 
     // 查找过期图像（基于 accessedAt，而非 createdAt）
@@ -279,20 +283,22 @@ export class ImageStorageService implements IImageStorageService {
    * 3. 超过 maxCacheSize 的部分（删除最旧的）
    */
   async enforceQuota(): Promise<void> {
-    const maxAge = this.config.maxAge!
+    const maxAge = this.config.maxAge
     const maxCount = this.config.maxCount!
     const maxCacheSize = this.config.maxCacheSize!
     const now = Date.now()
 
     // 1. 清理过期图像（基于 accessedAt）
-    const cutoffTime = now - maxAge
-    const expiredImages = await this.db.imageMetadata
-      .where('accessedAt')
-      .below(cutoffTime)
-      .primaryKeys()
+    if (typeof maxAge === 'number' && Number.isFinite(maxAge) && maxAge > 0) {
+      const cutoffTime = now - maxAge
+      const expiredImages = await this.db.imageMetadata
+        .where('accessedAt')
+        .below(cutoffTime)
+        .primaryKeys()
 
-    if (expiredImages.length > 0) {
-      await this.deleteImages(expiredImages)
+      if (expiredImages.length > 0) {
+        await this.deleteImages(expiredImages)
+      }
     }
 
     // 重新获取统计（只查询 metadata 表，性能优化）
diff --git a/packages/core/src/services/preference/service.ts b/packages/core/src/services/preference/service.ts
index 0a5d31cd..749b76b6 100644
--- a/packages/core/src/services/preference/service.ts
+++ b/packages/core/src/services/preference/service.ts
@@ -5,6 +5,40 @@ import { IMPORT_EXPORT_ERROR_CODES } from "../../constants/error-codes";
 import { StorageError } from "../storage/errors";
 import { toErrorWithCode } from "../../utils/error";
 
+const SESSION_KEY_PREFIX = "session/";
+const MAX_SESSION_SNAPSHOT_BYTES = 1024 * 1024;
+
+type SessionStorageOperation = "read" | "write";
+
+const getSerializedValueBytes = (value: string): number =>
+  new TextEncoder().encode(value).byteLength;
+
+const assertSessionSnapshotSize = (
+  key: string,
+  serializedValue: string,
+  operation: SessionStorageOperation,
+): void => {
+  if (!key.startsWith(SESSION_KEY_PREFIX)) {
+    return;
+  }
+
+  const bytes = getSerializedValueBytes(serializedValue);
+  if (bytes <= MAX_SESSION_SNAPSHOT_BYTES) {
+    return;
+  }
+
+  throw new StorageError(
+    `Session snapshot exceeds ${MAX_SESSION_SNAPSHOT_BYTES} bytes`,
+    operation,
+    {
+      reason: "session_snapshot_too_large",
+      key,
+      bytes,
+      limitBytes: MAX_SESSION_SNAPSHOT_BYTES,
+    },
+  );
+};
+
 // 需要导出的UI配置键 - 白名单验证
 const UI_SETTINGS_KEYS = [
   "app:settings:ui:theme-id",
@@ -91,6 +125,7 @@ export class PreferenceService implements IPreferenceService {
       if (storedValue === null) {
         return defaultValue;
       }
+      assertSessionSnapshotSize(key, storedValue, "read");
       // 将键添加到缓存中
       this.keyCache.add(key);
       return JSON.parse(storedValue) as T;
@@ -116,6 +151,7 @@ export class PreferenceService implements IPreferenceService {
     try {
       const prefKey = this.getPrefKey(key);
       const stringValue = JSON.stringify(value);
+      assertSessionSnapshotSize(key, stringValue, "write");
 
       await this.storageProvider.setItem(prefKey, stringValue);
       // 将键添加到缓存中
diff --git a/packages/core/src/services/storage/startup-safety-check.ts b/packages/core/src/services/storage/startup-safety-check.ts
new file mode 100644
index 00000000..72bee57e
--- /dev/null
+++ b/packages/core/src/services/storage/startup-safety-check.ts
@@ -0,0 +1,441 @@
+import type { IStorageProvider } from './types'
+import type { FavoritePrompt } from '../favorite/types'
+import {
+  FAVORITES_HARD_LIMIT_BYTES,
+  FAVORITES_SOFT_LIMIT_BYTES,
+  INLINE_IMAGE_DATA_URL_RE,
+  assertFavoritesPayloadWithinBudget,
+  getSerializedByteLength,
+  normalizeFavoriteRecord,
+} from '../favorite/storage-guards'
+
+const MAX_SESSION_SNAPSHOT_BYTES = 1024 * 1024
+const GENERIC_MAX_STRING_BYTES = 512 * 1024
+const CONTEXT_STORE_MAX_STRING_BYTES = 1024 * 1024
+
+const DEFAULT_SESSION_STORAGE_KEYS = [
+  'pref:session/v1/basic-system',
+  'pref:session/v1/basic-user',
+  'pref:session/v1/pro-multi',
+  'pref:session/v1/pro-variable',
+  'pref:session/v1/image-text2image',
+  'pref:session/v1/image-image2image',
+  'pref:session/v1/image-multiimage',
+] as const
+
+export const STARTUP_REPAIR_REPORT_PREFERENCE_KEY = 'startup-repair-report/v1'
+export const STARTUP_REPAIR_REPORT_STORAGE_KEY = `pref:${STARTUP_REPAIR_REPORT_PREFERENCE_KEY}`
+
+type StartupRepairReason =
+  | 'invalid_json'
+  | 'invalid_structure'
+  | 'inline_image_detected'
+  | 'abnormal_string_detected'
+  | 'budget_exceeded'
+  | 'invalid_entries_removed'
+  | 'budget_trimmed'
+  | 'soft_limit_exceeded'
+  | 'orphan_assets_removed'
+
+export interface StartupRepairAction {
+  key: string
+  action: 'removed' | 'rewritten' | 'warning'
+  reason: StartupRepairReason
+  droppedCount?: number
+  keptCount?: number
+  deletedCount?: number
+  details?: string
+}
+
+export interface StartupRepairReport {
+  checkedAt: number
+  actions: StartupRepairAction[]
+}
+
+type StorageWithOptionalKeyEnumeration = IStorageProvider & {
+  getAllKeys?: () => string[] | Promise<string[]>
+}
+
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+  !!value && typeof value === 'object' && !Array.isArray(value)
+
+const parseStoredJsonDocument = (raw: string): unknown => {
+  const parsed = JSON.parse(raw)
+  if (typeof parsed !== 'string') {
+    return parsed
+  }
+
+  const nested = parsed.trim()
+  if (!nested) {
+    return parsed
+  }
+
+  if (
+    (nested.startsWith('{') && nested.endsWith('}')) ||
+    (nested.startsWith('[') && nested.endsWith(']'))
+  ) {
+    return JSON.parse(nested)
+  }
+
+  return parsed
+}
+
+const findInlineImagePath = (
+  value: unknown,
+  path = '$',
+  seen: WeakSet<object> = new WeakSet(),
+): string | null => {
+  if (typeof value === 'string') {
+    return INLINE_IMAGE_DATA_URL_RE.test(value.trim()) ? path : null
+  }
+
+  if (!value || typeof value !== 'object') {
+    return null
+  }
+
+  if (seen.has(value as object)) {
+    return null
+  }
+  seen.add(value as object)
+
+  if (Array.isArray(value)) {
+    for (let index = 0; index < value.length; index += 1) {
+      const match = findInlineImagePath(value[index], `${path}[${index}]`, seen)
+      if (match) return match
+    }
+    return null
+  }
+
+  for (const [key, child] of Object.entries(value as Record<string, unknown>)) {
+    const match = findInlineImagePath(child, `${path}.${key}`, seen)
+    if (match) return match
+  }
+
+  return null
+}
+
+const findOversizedString = (
+  value: unknown,
+  maxBytes: number,
+  path = '$',
+  seen: WeakSet<object> = new WeakSet(),
+): { path: string; bytes: number } | null => {
+  if (typeof value === 'string') {
+    const bytes = getSerializedByteLength(value)
+    return bytes > maxBytes ? { path, bytes } : null
+  }
+
+  if (!value || typeof value !== 'object') {
+    return null
+  }
+
+  if (seen.has(value as object)) {
+    return null
+  }
+  seen.add(value as object)
+
+  if (Array.isArray(value)) {
+    for (let index = 0; index < value.length; index += 1) {
+      const match = findOversizedString(value[index], maxBytes, `${path}[${index}]`, seen)
+      if (match) return match
+    }
+    return null
+  }
+
+  for (const [key, child] of Object.entries(value as Record<string, unknown>)) {
+    const match = findOversizedString(child, maxBytes, `${path}.${key}`, seen)
+    if (match) return match
+  }
+
+  return null
+}
+
+const isValidGlobalSettings = (value: unknown): boolean => {
+  if (!isPlainObject(value)) return false
+
+  const functionMode = value.functionMode
+  const basicSubMode = value.basicSubMode
+  const proSubMode = value.proSubMode
+  const imageSubMode = value.imageSubMode
+
+  return (
+    (value.selectedThemeId === undefined || typeof value.selectedThemeId === 'string') &&
+    (value.preferredLanguage === undefined || typeof value.preferredLanguage === 'string') &&
+    (value.builtinTemplateLanguage === undefined || typeof value.builtinTemplateLanguage === 'string') &&
+    (functionMode === undefined || functionMode === 'basic' || functionMode === 'pro' || functionMode === 'image') &&
+    (basicSubMode === undefined || basicSubMode === 'system' || basicSubMode === 'user') &&
+    (proSubMode === undefined || proSubMode === 'multi' || proSubMode === 'variable') &&
+    (
+      imageSubMode === undefined ||
+      imageSubMode === 'text2image' ||
+      imageSubMode === 'image2image' ||
+      imageSubMode === 'multiimage'
+    ) &&
+    (value.lastActiveAt === undefined || typeof value.lastActiveAt === 'number')
+  )
+}
+
+const isValidContextStore = (value: unknown): boolean =>
+  isPlainObject(value) &&
+  typeof value.currentId === 'string' &&
+  isPlainObject(value.contexts)
+
+const isValidVariableStorage = (value: unknown): boolean => {
+  if (!isPlainObject(value)) return false
+
+  const customVariables = value.customVariables
+  if (customVariables !== undefined) {
+    if (!isPlainObject(customVariables)) return false
+    const invalidEntry = Object.values(customVariables).some((item) => typeof item !== 'string')
+    if (invalidEntry) return false
+  }
+
+  return (
+    (value.advancedModeEnabled === undefined || typeof value.advancedModeEnabled === 'boolean') &&
+    (
+      value.lastConversationMessages === undefined ||
+      Array.isArray(value.lastConversationMessages)
+    )
+  )
+}
+
+const isValidSessionSnapshot = (value: unknown): boolean =>
+  Array.isArray(value) || isPlainObject(value)
+
+const removeKeyAndReport = async (
+  storageProvider: IStorageProvider,
+  report: StartupRepairReport,
+  action: StartupRepairAction,
+): Promise<void> => {
+  await storageProvider.removeItem(action.key)
+  report.actions.push(action)
+}
+
+const validateStructuredKey = async (
+  storageProvider: IStorageProvider,
+  report: StartupRepairReport,
+  options: {
+    key: string
+    validator: (value: unknown) => boolean
+    maxStringBytes: number
+    hardLimitBytes?: number
+  },
+): Promise<void> => {
+  const raw = await storageProvider.getItem(options.key)
+  if (raw === null) {
+    return
+  }
+
+  if (
+    typeof options.hardLimitBytes === 'number' &&
+    getSerializedByteLength(raw) > options.hardLimitBytes
+  ) {
+    await removeKeyAndReport(storageProvider, report, {
+      key: options.key,
+      action: 'removed',
+      reason: 'budget_exceeded',
+    })
+    return
+  }
+
+  let parsed: unknown
+  try {
+    parsed = parseStoredJsonDocument(raw)
+  } catch {
+    await removeKeyAndReport(storageProvider, report, {
+      key: options.key,
+      action: 'removed',
+      reason: 'invalid_json',
+    })
+    return
+  }
+
+  if (!options.validator(parsed)) {
+    await removeKeyAndReport(storageProvider, report, {
+      key: options.key,
+      action: 'removed',
+      reason: 'invalid_structure',
+    })
+    return
+  }
+
+  const inlineImagePath = findInlineImagePath(parsed)
+  if (inlineImagePath) {
+    await removeKeyAndReport(storageProvider, report, {
+      key: options.key,
+      action: 'removed',
+      reason: 'inline_image_detected',
+      details: inlineImagePath,
+    })
+    return
+  }
+
+  const oversizedString = findOversizedString(parsed, options.maxStringBytes)
+  if (oversizedString) {
+    await removeKeyAndReport(storageProvider, report, {
+      key: options.key,
+      action: 'removed',
+      reason: 'abnormal_string_detected',
+      details: `${oversizedString.path} (${oversizedString.bytes} bytes)`,
+    })
+  }
+}
+
+const sortFavoritesByUpdatedAtDesc = (favorites: FavoritePrompt[]): FavoritePrompt[] =>
+  [...favorites].sort((left, right) => right.updatedAt - left.updatedAt)
+
+const trimFavoritesToBudget = (favorites: FavoritePrompt[]): FavoritePrompt[] => {
+  const kept: FavoritePrompt[] = []
+
+  sortFavoritesByUpdatedAtDesc(favorites).forEach((favorite) => {
+    const candidate = [...kept, favorite]
+    const totalBytes = getSerializedByteLength(JSON.stringify(candidate))
+    if (totalBytes <= FAVORITES_HARD_LIMIT_BYTES) {
+      kept.push(favorite)
+    }
+  })
+
+  return kept
+}
+
+const repairFavoritesKey = async (
+  storageProvider: IStorageProvider,
+  report: StartupRepairReport,
+): Promise<void> => {
+  const raw = await storageProvider.getItem('favorites')
+  if (raw === null) {
+    return
+  }
+
+  let parsed: unknown
+  try {
+    parsed = JSON.parse(raw)
+  } catch {
+    await removeKeyAndReport(storageProvider, report, {
+      key: 'favorites',
+      action: 'removed',
+      reason: 'invalid_json',
+    })
+    return
+  }
+
+  if (!Array.isArray(parsed)) {
+    await removeKeyAndReport(storageProvider, report, {
+      key: 'favorites',
+      action: 'removed',
+      reason: 'invalid_structure',
+    })
+    return
+  }
+
+  const sanitizedFavorites: FavoritePrompt[] = []
+  let droppedCount = 0
+  const fallbackTimestamp = Date.now()
+
+  parsed.forEach((item, index) => {
+    try {
+      sanitizedFavorites.push(normalizeFavoriteRecord(item, fallbackTimestamp + index))
+    } catch {
+      droppedCount += 1
+    }
+  })
+
+  let finalFavorites = sanitizedFavorites
+  let reason: StartupRepairReason | null = droppedCount > 0 ? 'invalid_entries_removed' : null
+
+  try {
+    const { totalBytes } = assertFavoritesPayloadWithinBudget(finalFavorites)
+    if (totalBytes > FAVORITES_SOFT_LIMIT_BYTES) {
+      report.actions.push({
+        key: 'favorites',
+        action: 'warning',
+        reason: 'soft_limit_exceeded',
+        keptCount: finalFavorites.length,
+      })
+    }
+  } catch {
+    finalFavorites = trimFavoritesToBudget(finalFavorites)
+    reason = 'budget_trimmed'
+  }
+
+  const serializedFinalFavorites = JSON.stringify(finalFavorites)
+  if (serializedFinalFavorites !== raw || reason) {
+    await storageProvider.setItem('favorites', serializedFinalFavorites)
+    report.actions.push({
+      key: 'favorites',
+      action: 'rewritten',
+      reason: reason || 'invalid_entries_removed',
+      droppedCount: parsed.length - finalFavorites.length,
+      keptCount: finalFavorites.length,
+    })
+  }
+}
+
+const collectSessionStorageKeys = async (storageProvider: StorageWithOptionalKeyEnumeration): Promise<string[]> => {
+  const enumeratedKeys = typeof storageProvider.getAllKeys === 'function'
+    ? await storageProvider.getAllKeys()
+    : []
+
+  return Array.from(
+    new Set([
+      ...DEFAULT_SESSION_STORAGE_KEYS,
+      ...enumeratedKeys.filter((key) => key.startsWith('pref:session/v1/')),
+    ]),
+  )
+}
+
+export async function writeStartupRepairReport(
+  storageProvider: IStorageProvider,
+  report: StartupRepairReport,
+): Promise<void> {
+  if (report.actions.length === 0) {
+    await storageProvider.removeItem(STARTUP_REPAIR_REPORT_STORAGE_KEY)
+    return
+  }
+
+  await storageProvider.setItem(
+    STARTUP_REPAIR_REPORT_STORAGE_KEY,
+    JSON.stringify(report),
+  )
+}
+
+export async function runStorageStartupSafetyCheck(
+  storageProvider: IStorageProvider,
+): Promise<StartupRepairReport> {
+  const report: StartupRepairReport = {
+    checkedAt: Date.now(),
+    actions: [],
+  }
+
+  await validateStructuredKey(storageProvider, report, {
+    key: 'pref:global-settings/v1',
+    validator: isValidGlobalSettings,
+    maxStringBytes: GENERIC_MAX_STRING_BYTES,
+  })
+
+  const sessionKeys = await collectSessionStorageKeys(storageProvider as StorageWithOptionalKeyEnumeration)
+  for (const key of sessionKeys) {
+    await validateStructuredKey(storageProvider, report, {
+      key,
+      validator: isValidSessionSnapshot,
+      maxStringBytes: MAX_SESSION_SNAPSHOT_BYTES,
+      hardLimitBytes: MAX_SESSION_SNAPSHOT_BYTES,
+    })
+  }
+
+  await validateStructuredKey(storageProvider, report, {
+    key: 'ctx:store',
+    validator: isValidContextStore,
+    maxStringBytes: CONTEXT_STORE_MAX_STRING_BYTES,
+  })
+
+  await validateStructuredKey(storageProvider, report, {
+    key: 'pref:variableManager.storage',
+    validator: isValidVariableStorage,
+    maxStringBytes: GENERIC_MAX_STRING_BYTES,
+  })
+
+  await repairFavoritesKey(storageProvider, report)
+
+  return report
+}
diff --git a/packages/core/tests/services/favorite/manager-extended.test.ts b/packages/core/tests/services/favorite/manager-extended.test.ts
index 2305acc9..e6b6e30b 100644
--- a/packages/core/tests/services/favorite/manager-extended.test.ts
+++ b/packages/core/tests/services/favorite/manager-extended.test.ts
@@ -217,6 +217,128 @@ describe('FavoriteManager - 扩展功能', () => {
       expect(favorite.metadata?.customField).toBe('自定义值');
       expect(favorite.metadata?.anotherField).toBe(123);
     });
+
+    it('应该拒绝包含 data URL 封面的收藏 metadata', async () => {
+      await expect(
+        manager.addFavorite({
+          title: '测试',
+          content: '内容',
+          tags: [],
+          functionMode: 'basic',
+          optimizationMode: 'system',
+          metadata: {
+            media: {
+              coverUrl: 'data:image/png;base64,AAAA',
+            },
+          },
+        })
+      ).rejects.toThrow(FavoriteValidationError);
+    });
+
+    it('应该拒绝在更新时写入包含 data URL 的 gardenSnapshot 图片', async () => {
+      const id = await manager.addFavorite({
+        title: '测试',
+        content: '内容',
+        tags: [],
+        functionMode: 'basic',
+        optimizationMode: 'system',
+      });
+
+      await expect(
+        manager.updateFavorite(id, {
+          metadata: {
+            gardenSnapshot: {
+              assets: {
+                showcases: [
+                  {
+                    images: ['data:image/png;base64,BBBB'],
+                  },
+                ],
+              },
+            },
+          },
+        })
+      ).rejects.toThrow(FavoriteValidationError);
+    });
+  });
+
+  describe('favorites 存储防线', () => {
+    const buildFavoriteInput = (overrides: Record<string, unknown> = {}) => ({
+      title: '测试收藏',
+      content: '内容',
+      tags: [],
+      functionMode: 'basic' as const,
+      optimizationMode: 'system' as const,
+      ...overrides,
+    });
+
+    const buildStoredFavorite = (id: string, contentSizeBytes: number, updatedAt = Date.now()) => ({
+      id,
+      title: `收藏 ${id}`,
+      content: 'x'.repeat(contentSizeBytes),
+      tags: [],
+      functionMode: 'basic' as const,
+      optimizationMode: 'system' as const,
+      createdAt: updatedAt,
+      updatedAt,
+      useCount: 0,
+    });
+
+    it('应该拒绝写入超过 512 KiB 的单条收藏', async () => {
+      await expect(
+        manager.addFavorite(
+          buildFavoriteInput({
+            content: 'x'.repeat(520 * 1024),
+          }),
+        ),
+      ).rejects.toThrow(FavoriteValidationError);
+    });
+
+    it('应该拒绝将更新后的单条收藏扩张到超过 512 KiB', async () => {
+      const id = await manager.addFavorite(buildFavoriteInput());
+
+      await expect(
+        manager.updateFavorite(id, {
+          content: 'x'.repeat(520 * 1024),
+        }),
+      ).rejects.toThrow(FavoriteValidationError);
+    });
+
+    it('应该拒绝写入后整体 favorites payload 超过 8 MiB', async () => {
+      const existingFavorites = Array.from({ length: 16 }, (_, index) =>
+        buildStoredFavorite(`fav-${index + 1}`, 500 * 1024, 1_700_000_000_000 + index),
+      );
+      mockStorage.set('favorites', JSON.stringify(existingFavorites));
+
+      await expect(
+        manager.addFavorite(
+          buildFavoriteInput({
+            title: '会超限的收藏',
+            content: 'y'.repeat(500 * 1024),
+          }),
+        ),
+      ).rejects.toThrow(FavoriteValidationError);
+    });
+
+    it('在超过 2 MiB 但未达到 8 MiB 时应该允许写入并记录 warning', async () => {
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
+      const existingFavorites = Array.from({ length: 4 }, (_, index) =>
+        buildStoredFavorite(`fav-soft-${index + 1}`, 500 * 1024, 1_700_000_100_000 + index),
+      );
+      mockStorage.set('favorites', JSON.stringify(existingFavorites));
+
+      const id = await manager.addFavorite(
+        buildFavoriteInput({
+          title: '接近上限的收藏',
+          content: 'z'.repeat(40 * 1024),
+        }),
+      );
+
+      expect(id).toBeTruthy();
+      expect(warnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('favorites payload exceeds soft limit'),
+      );
+    });
   });
 
   describe('分类管理 - reorderCategories', () => {
diff --git a/packages/core/tests/unit/preference/service.test.ts b/packages/core/tests/unit/preference/service.test.ts
index 1ab9249a..619b1346 100644
--- a/packages/core/tests/unit/preference/service.test.ts
+++ b/packages/core/tests/unit/preference/service.test.ts
@@ -139,6 +139,40 @@ describe('PreferenceService', () => {
   });
 
   describe('错误处理', () => {
+    it('should reject oversized session snapshots on write', async () => {
+      const oversizedValue = {
+        payload: 'x'.repeat(1024 * 1024 + 128),
+      }
+
+      await expect(
+        preferenceService.set('session/v1/image-multiimage', oversizedValue)
+      ).rejects.toMatchObject({
+        code: 'error.storage.write',
+        params: expect.objectContaining({
+          reason: 'session_snapshot_too_large',
+          key: 'session/v1/image-multiimage',
+        }),
+      })
+    });
+
+    it('should reject oversized session snapshots on read before parsing', async () => {
+      const oversizedRaw = JSON.stringify({
+        payload: 'x'.repeat(1024 * 1024 + 128),
+      })
+
+      await mockStorage.setItem('pref:session/v1/image-multiimage', oversizedRaw)
+
+      await expect(
+        preferenceService.get('session/v1/image-multiimage', null)
+      ).rejects.toMatchObject({
+        code: 'error.storage.read',
+        params: expect.objectContaining({
+          reason: 'session_snapshot_too_large',
+          key: 'session/v1/image-multiimage',
+        }),
+      })
+    });
+
     it('should handle storage errors in get', async () => {
       const mockStorageWithError = {
         getItem: vi.fn().mockRejectedValue(new Error('Storage error')),
diff --git a/packages/core/tests/unit/storage/startup-safety-check.test.ts b/packages/core/tests/unit/storage/startup-safety-check.test.ts
new file mode 100644
index 00000000..ef2b1d6e
--- /dev/null
+++ b/packages/core/tests/unit/storage/startup-safety-check.test.ts
@@ -0,0 +1,159 @@
+import { describe, it, expect } from 'vitest'
+
+import { MemoryStorageProvider } from '../../../src/services/storage/memoryStorageProvider'
+import { runStorageStartupSafetyCheck } from '../../../src/services/storage/startup-safety-check'
+
+const buildFavorite = (id: string, overrides: Record<string, unknown> = {}) => ({
+  id,
+  title: `收藏 ${id}`,
+  content: '有效内容',
+  tags: [],
+  functionMode: 'basic' as const,
+  optimizationMode: 'system' as const,
+  createdAt: 1_700_000_000_000,
+  updatedAt: 1_700_000_000_000,
+  useCount: 0,
+  ...overrides,
+})
+
+describe('runStorageStartupSafetyCheck', () => {
+  it('removes a broken global-settings key and keeps the app bootable', async () => {
+    const storage = new MemoryStorageProvider()
+    await storage.setItem('pref:global-settings/v1', '{invalid json')
+
+    const report = await runStorageStartupSafetyCheck(storage)
+
+    expect(await storage.getItem('pref:global-settings/v1')).toBeNull()
+    expect(report.actions).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          key: 'pref:global-settings/v1',
+          action: 'removed',
+        }),
+      ]),
+    )
+  })
+
+  it('removes a broken ctx:store key and preserves unrelated data', async () => {
+    const storage = new MemoryStorageProvider()
+    await storage.setItem(
+      'ctx:store',
+      JSON.stringify({
+        currentId: 123,
+      }),
+    )
+    await storage.setItem(
+      'pref:global-settings/v1',
+      JSON.stringify({
+        version: 1,
+        theme: 'light',
+      }),
+    )
+
+    await runStorageStartupSafetyCheck(storage)
+
+    expect(await storage.getItem('ctx:store')).toBeNull()
+    expect(await storage.getItem('pref:global-settings/v1')).not.toBeNull()
+  })
+
+  it('removes only the oversized session snapshot and leaves other sessions untouched', async () => {
+    const storage = new MemoryStorageProvider()
+    await storage.setItem(
+      'pref:session/v1/image-multiimage',
+      JSON.stringify({
+        payload: 'x'.repeat(1024 * 1024 + 128),
+      }),
+    )
+    await storage.setItem(
+      'pref:session/v1/basic-system',
+      JSON.stringify({
+        prompt: 'safe',
+      }),
+    )
+
+    const report = await runStorageStartupSafetyCheck(storage)
+
+    expect(await storage.getItem('pref:session/v1/image-multiimage')).toBeNull()
+    expect(await storage.getItem('pref:session/v1/basic-system')).toBe(
+      JSON.stringify({
+        prompt: 'safe',
+      }),
+    )
+    expect(report.actions).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          key: 'pref:session/v1/image-multiimage',
+          action: 'removed',
+          reason: 'budget_exceeded',
+        }),
+      ]),
+    )
+  })
+
+  it('salvages valid favorites and drops invalid, inline-image, and oversized entries', async () => {
+    const storage = new MemoryStorageProvider()
+    await storage.setItem(
+      'favorites',
+      JSON.stringify([
+        buildFavorite('fav-valid'),
+        'bad-item',
+        buildFavorite('fav-inline', {
+          metadata: {
+            media: {
+              coverUrl: 'data:image/png;base64,AAAA',
+            },
+          },
+        }),
+        buildFavorite('fav-too-large', {
+          content: 'x'.repeat(520 * 1024),
+        }),
+      ]),
+    )
+
+    const report = await runStorageStartupSafetyCheck(storage)
+    const repairedRaw = await storage.getItem('favorites')
+    const repairedFavorites = repairedRaw ? JSON.parse(repairedRaw) : []
+
+    expect(repairedFavorites).toHaveLength(1)
+    expect(repairedFavorites[0].id).toBe('fav-valid')
+    expect(report.actions).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          key: 'favorites',
+          action: 'rewritten',
+          droppedCount: 3,
+        }),
+      ]),
+    )
+  })
+
+  it('trims an oversized favorites payload by keeping the newest entries first', async () => {
+    const storage = new MemoryStorageProvider()
+    const favorites = Array.from({ length: 20 }, (_, index) =>
+      buildFavorite(`fav-${index + 1}`, {
+        content: 'x'.repeat(500 * 1024),
+        createdAt: 1_700_000_000_000 + index,
+        updatedAt: 1_700_000_000_000 + index,
+      }),
+    )
+    await storage.setItem('favorites', JSON.stringify(favorites))
+
+    const report = await runStorageStartupSafetyCheck(storage)
+    const repairedRaw = await storage.getItem('favorites')
+    const repairedFavorites = repairedRaw ? JSON.parse(repairedRaw) : []
+
+    expect(repairedFavorites.length).toBeLessThan(favorites.length)
+    expect(repairedFavorites[0].updatedAt).toBeGreaterThan(repairedFavorites[repairedFavorites.length - 1].updatedAt)
+    expect(repairedFavorites.some((favorite: { id: string }) => favorite.id === 'fav-20')).toBe(true)
+    expect(repairedFavorites.some((favorite: { id: string }) => favorite.id === 'fav-1')).toBe(false)
+    expect(report.actions).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          key: 'favorites',
+          action: 'rewritten',
+          reason: 'budget_trimmed',
+        }),
+      ]),
+    )
+  })
+})
diff --git a/packages/desktop/main.js b/packages/desktop/main.js
index e98456ca..b3de7f74 100644
--- a/packages/desktop/main.js
+++ b/packages/desktop/main.js
@@ -67,6 +67,8 @@ const {
   createContextRepo,
   FavoriteManager,
   FileStorageProvider,
+  runStorageStartupSafetyCheck,
+  writeStartupRepairReport,
   // 导入共享的环境变量扫描常量
   CUSTOM_API_PATTERN,
   SUFFIX_PATTERN,
@@ -593,6 +595,8 @@ async function initializeServices() {
     const userDataPath = app.getPath('userData');
     console.log('[DESKTOP] Using standard user data directory for auto-update compatibility:', userDataPath);
     storageProvider = new FileStorageProvider(userDataPath);
+    const startupRepairReport = await runStorageStartupSafetyCheck(storageProvider);
+    await writeStartupRepairReport(storageProvider, startupRepairReport);
     
     await initializePreferenceService(storageProvider);
     
diff --git a/packages/ui/src/components/app-layout/PromptOptimizerApp.vue b/packages/ui/src/components/app-layout/PromptOptimizerApp.vue
index fa85b776..c18edff3 100644
--- a/packages/ui/src/components/app-layout/PromptOptimizerApp.vue
+++ b/packages/ui/src/components/app-layout/PromptOptimizerApp.vue
@@ -386,7 +386,26 @@ const handleUnhandledRejection = (event: PromiseRejectionEvent) => {
 };
 
 // 2. 初始化应用服务
-const { services, isInitializing } = useAppInitializer();
+const { services, isInitializing, startupRepairReport } = useAppInitializer();
+
+const hasShownStartupRepairToast = ref(false)
+
+watch(
+  [isInitializing, startupRepairReport],
+  ([initializing, report]) => {
+    if (initializing || !report || hasShownStartupRepairToast.value) {
+      return
+    }
+
+    if (!Array.isArray(report.actions) || report.actions.length === 0) {
+      return
+    }
+
+    hasShownStartupRepairToast.value = true
+    toast.warning(`启动时已自动修复 ${report.actions.length} 项本地存储异常。`)
+  },
+  { immediate: true },
+)
 
 // 3. 初始化功能模式和子模式（必须在 sessionManager 之前）
 //
diff --git a/packages/ui/src/composables/app/useAppPromptGardenImport.ts b/packages/ui/src/composables/app/useAppPromptGardenImport.ts
index d7d1b476..e9e216ea 100644
--- a/packages/ui/src/composables/app/useAppPromptGardenImport.ts
+++ b/packages/ui/src/composables/app/useAppPromptGardenImport.ts
@@ -311,7 +311,11 @@ const saveImportedPromptToFavorites = async (opts: {
   }
 
   const modeMapping = toFavoriteModeMapping(targetKey)
-  const snapshot = await buildStorableGardenSnapshot(fetched.gardenSnapshot, imageStorageService)
+  const snapshot = await buildStorableGardenSnapshot(
+    fetched.gardenSnapshot,
+    imageStorageService,
+    { allowImageFallback: false },
+  )
   const media = buildFavoriteMediaFromSnapshot(snapshot)
   const favorites = await manager.getFavorites()
   const existing = favorites.find((favorite) => isSameGardenSnapshotFavorite(favorite, snapshot))
@@ -840,11 +844,22 @@ const persistSourcesToAssetIdsWithFallback = async (opts: {
   sources: string[]
   storageService: IImageStorageService | null | undefined
   metadata?: { prompt?: string }
+  allowSourceFallback?: boolean
 }): Promise<{ assetIds: string[]; fallbackSources: string[] }> => {
-  const { storageService, metadata } = opts
+  const { storageService, metadata, allowSourceFallback = true } = opts
   const normalizedSources = dedupeStrings(opts.sources.map((item) => String(item || '').trim()).filter(Boolean))
 
-  if (!storageService || normalizedSources.length === 0) {
+  if (normalizedSources.length === 0) {
+    return {
+      assetIds: [],
+      fallbackSources: normalizedSources,
+    }
+  }
+
+  if (!storageService) {
+    if (!allowSourceFallback) {
+      throw new Error('Favorite image storage service unavailable')
+    }
     return {
       assetIds: [],
       fallbackSources: normalizedSources,
@@ -865,11 +880,16 @@ const persistSourcesToAssetIdsWithFallback = async (opts: {
 
       if (assetId) {
         assetIds.push(assetId)
+      } else if (!allowSourceFallback) {
+        throw new Error(`Failed to persist snapshot image source: ${source}`)
       } else {
         fallbackSources.push(source)
       }
     } catch (error) {
       console.warn('[PromptGardenImport] Failed to persist snapshot image source:', source, error)
+      if (!allowSourceFallback) {
+        throw error
+      }
       fallbackSources.push(source)
     }
   }
@@ -884,8 +904,9 @@ const persistSnapshotAssetItem = async (opts: {
   item: GardenSnapshotAssetItem
   storageService: IImageStorageService | null | undefined
   metadata?: { prompt?: string }
+  allowSourceFallback?: boolean
 }): Promise<GardenSnapshotAssetItem> => {
-  const { storageService, metadata } = opts
+  const { storageService, metadata, allowSourceFallback = true } = opts
   const next: GardenSnapshotAssetItem = { ...opts.item }
 
   const imageSources = dedupeStrings([
@@ -897,6 +918,7 @@ const persistSnapshotAssetItem = async (opts: {
     sources: imageSources,
     storageService,
     metadata,
+    allowSourceFallback,
   })
 
   const existingImageAssetIds = extractStringArray(next.imageAssetIds)
@@ -915,6 +937,7 @@ const persistSnapshotAssetItem = async (opts: {
     sources: inputSources,
     storageService,
     metadata,
+    allowSourceFallback,
   })
 
   const existingInputAssetIds = extractStringArray(next.inputImageAssetIds)
@@ -927,9 +950,13 @@ const persistSnapshotAssetItem = async (opts: {
 async function buildStorableGardenSnapshot(
   snapshot: GardenSnapshot,
   imageStorageService?: IImageStorageService | null,
+  options?: {
+    allowImageFallback?: boolean
+  },
 ): Promise<GardenSnapshot> {
   const assets = snapshot.assets || {}
   const sourceMetadata = buildAssetSourceMetadata(snapshot)
+  const allowImageFallback = options?.allowImageFallback ?? true
 
   const cover = assets.cover ? { ...assets.cover } : undefined
   if (cover && typeof cover.url === 'string') {
@@ -943,9 +970,14 @@ async function buildStorableGardenSnapshot(
       if (coverAssetId) {
         cover.assetId = coverAssetId
         delete cover.url
+      } else if (!allowImageFallback) {
+        throw new Error(`Failed to persist cover image source: ${cover.url}`)
       }
     } catch (error) {
-      console.warn('[PromptGardenImport] Failed to persist cover image source:', cover.url, error)
+      console.info('[PromptGardenImport] Failed to persist cover image source:', cover.url, error)
+      if (!allowImageFallback) {
+        throw error
+      }
     }
   }
 
@@ -956,6 +988,7 @@ async function buildStorableGardenSnapshot(
             item,
             storageService: imageStorageService,
             metadata: sourceMetadata,
+            allowSourceFallback: allowImageFallback,
           }),
         ),
       )
@@ -968,6 +1001,7 @@ async function buildStorableGardenSnapshot(
             item,
             storageService: imageStorageService,
             metadata: sourceMetadata,
+            allowSourceFallback: allowImageFallback,
           }),
         ),
       )
@@ -1389,7 +1423,7 @@ export function useAppPromptGardenImport(options: AppPromptGardenImportOptions)
                 targetKey,
               })
             } catch (error) {
-              console.warn('[PromptGardenImport] Auto-save to favorites failed:', error)
+              toast.warning('Prompt Garden 导入成功，但收藏未保存。')
             }
           } else {
             console.warn('[PromptGardenImport] Favorite manager unavailable, skip auto-save')
@@ -1406,16 +1440,24 @@ export function useAppPromptGardenImport(options: AppPromptGardenImportOptions)
               getFavoriteImageStorageService?.() || getImageStorageService?.() || null
 
             let snapshot = fetched.gardenSnapshot
+            let includeMedia = true
             try {
-              snapshot = await buildStorableGardenSnapshot(snapshot, imageStorageService)
+              snapshot = await buildStorableGardenSnapshot(snapshot, imageStorageService, {
+                allowImageFallback: false,
+              })
             } catch (error) {
-              console.warn('[PromptGardenImport] Failed to persist snapshot assets for favorite dialog:', error)
+              console.info('[PromptGardenImport] Failed to persist snapshot assets for favorite dialog:', error)
+              includeMedia = false
             }
 
-            const media = buildFavoriteMediaFromSnapshot(snapshot)
             const metadata: Record<string, unknown> = {
               gardenSnapshot: snapshot,
-              ...(media ? { media } : {}),
+              ...(includeMedia
+                ? (() => {
+                    const media = buildFavoriteMediaFromSnapshot(snapshot)
+                    return media ? { media } : {}
+                  })()
+                : {}),
             }
 
             openSaveFavoriteDialog({
diff --git a/packages/ui/src/composables/system/useAppInitializer.ts b/packages/ui/src/composables/system/useAppInitializer.ts
index c0bc76bb..9d03b8df 100644
--- a/packages/ui/src/composables/system/useAppInitializer.ts
+++ b/packages/ui/src/composables/system/useAppInitializer.ts
@@ -2,6 +2,7 @@ import { ref, shallowRef, onMounted, type Ref } from 'vue'
 
 import {
   StorageFactory,
+  STARTUP_REPAIR_REPORT_PREFERENCE_KEY,
   createModelManager,
   createTemplateManager,
   createHistoryManager,
@@ -33,6 +34,8 @@ import {
   createImageAdapterRegistry,
   createTextAdapterRegistry,
   createImageStorageService,
+  runStorageStartupSafetyCheck,
+  writeStartupRepairReport,
   // migrateLegacySessions - 已移除，session 是本次重构新引入
   type IImageModelManager,
   type IImageService,
@@ -49,11 +52,39 @@ import {
   type IVariableExtractionService,
   type IVariableValueGenerationService,
   type IImageStorageService,
+  type StartupRepairReport,
   type ContextMode,
   DEFAULT_CONTEXT_MODE
 } from '@prompt-optimizer/core';
 import type { AppServices } from '../../types/services';
 import { scheduleImageStorageGc } from '../../stores/session/imageStorageMaintenance'
+import {
+  attachFavoriteAssetGc,
+  runFavoriteAssetGc,
+} from '../../utils/favorite-asset-maintenance'
+
+const appendStartupRepairReport = (
+  currentReport: StartupRepairReport | null,
+  nextAction: StartupRepairReport['actions'][number],
+): StartupRepairReport => ({
+  checkedAt: currentReport?.checkedAt ?? Date.now(),
+  actions: [...(currentReport?.actions || []), nextAction],
+})
+
+const consumeStartupRepairReport = async (
+  preferenceService: IPreferenceService,
+): Promise<StartupRepairReport | null> => {
+  const report = await preferenceService.get<StartupRepairReport | null>(
+    STARTUP_REPAIR_REPORT_PREFERENCE_KEY,
+    null,
+  )
+
+  if (report) {
+    await preferenceService.delete(STARTUP_REPAIR_REPORT_PREFERENCE_KEY)
+  }
+
+  return report
+}
 
 /**
  * 应用服务统一初始化器。
@@ -64,10 +95,12 @@ export function useAppInitializer(): {
   services: Ref<AppServices | null>;
   isInitializing: Ref<boolean>;
   error: Ref<Error | null>;
+  startupRepairReport: Ref<StartupRepairReport | null>;
 } {
   const services = shallowRef<AppServices | null>(null);
   const isInitializing = ref(true);
   const error = ref<Error | null>(null);
+  const startupRepairReport = ref<StartupRepairReport | null>(null);
 
   onMounted(async () => {
     try {
@@ -113,6 +146,7 @@ export function useAppInitializer(): {
         llmService = new ElectronLLMProxy();
         promptService = new ElectronPromptServiceProxy();
         preferenceService = new ElectronPreferenceServiceProxy();
+        startupRepairReport.value = await consumeStartupRepairReport(preferenceService)
 
         // 文本模型适配器注册表（本地实例，不需要代理）
         textAdapterRegistryInstance = createTextAdapterRegistry();
@@ -136,7 +170,7 @@ export function useAppInitializer(): {
         // 收藏快照图像存储（独立数据库，避免与 session 图片清理策略耦合）
         favoriteImageStorageService = createImageStorageService({
           maxCacheSize: 200 * 1024 * 1024,      // 200 MB
-          maxAge: 365 * 24 * 60 * 60 * 1000,    // 365 天
+          maxAge: undefined,
           maxCount: 1000,
           autoCleanupThreshold: 0.9,
           dbName: 'PromptOptimizerFavoriteImageDB',
@@ -157,6 +191,22 @@ export function useAppInitializer(): {
         // 创建收藏管理器代理
         const { FavoriteManagerElectronProxy } = await import('@prompt-optimizer/core')
         favoriteManager = new FavoriteManagerElectronProxy();
+        favoriteManager = attachFavoriteAssetGc(favoriteManager as any, favoriteImageStorageService)
+
+        if (favoriteImageStorageService) {
+          const favoriteAssetGcResult = await runFavoriteAssetGc(
+            favoriteManager,
+            favoriteImageStorageService,
+          )
+          if (favoriteAssetGcResult.deletedIds.length > 0) {
+            startupRepairReport.value = appendStartupRepairReport(startupRepairReport.value, {
+              key: 'PromptOptimizerFavoriteImageDB',
+              action: 'removed',
+              reason: 'orphan_assets_removed',
+              deletedCount: favoriteAssetGcResult.deletedIds.length,
+            })
+          }
+        }
 
         // 🆕 创建评估服务（使用代理的 llmService, modelManager, templateManager）
         evaluationService = createEvaluationService(llmService, modelManager, templateManager, {
@@ -220,9 +270,12 @@ export function useAppInitializer(): {
         console.log('[AppInitializer] 检测到Web环境，初始化完整服务...');
         // 在Web环境中，我们创建一套完整的、真实的服务
         const storageProvider = StorageFactory.create('dexie');
+        const stage1StartupRepairReport = await runStorageStartupSafetyCheck(storageProvider)
+        await writeStartupRepairReport(storageProvider, stage1StartupRepairReport)
 
         // 创建基于存储提供器的偏好设置服务，使用core包中的createPreferenceService
         preferenceService = createPreferenceService(storageProvider);
+        startupRepairReport.value = await consumeStartupRepairReport(preferenceService)
 
         const languageService = createTemplateLanguageService(preferenceService);
         
@@ -250,7 +303,7 @@ export function useAppInitializer(): {
         // 收藏快照图像存储（独立数据库，避免与 session 图片清理策略耦合）
         favoriteImageStorageService = createImageStorageService({
           maxCacheSize: 200 * 1024 * 1024,      // 200 MB
-          maxAge: 365 * 24 * 60 * 60 * 1000,    // 365 天
+          maxAge: undefined,
           maxCount: 1000,
           autoCleanupThreshold: 0.9,
           dbName: 'PromptOptimizerFavoriteImageDB',
@@ -370,6 +423,22 @@ export function useAppInitializer(): {
 
         // 创建收藏管理器
         favoriteManager = new FavoriteManager(storageProvider);
+        favoriteManager = attachFavoriteAssetGc(favoriteManager as any, favoriteImageStorageService)
+
+        if (favoriteImageStorageService) {
+          const favoriteAssetGcResult = await runFavoriteAssetGc(
+            favoriteManager,
+            favoriteImageStorageService,
+          )
+          if (favoriteAssetGcResult.deletedIds.length > 0) {
+            startupRepairReport.value = appendStartupRepairReport(startupRepairReport.value, {
+              key: 'PromptOptimizerFavoriteImageDB',
+              action: 'removed',
+              reason: 'orphan_assets_removed',
+              deletedCount: favoriteAssetGcResult.deletedIds.length,
+            })
+          }
+        }
 
         // 🆕 创建评估服务
         evaluationService = createEvaluationService(llmService, modelManagerAdapter, templateManagerAdapter, {
@@ -443,5 +512,5 @@ export function useAppInitializer(): {
     }
   });
 
-  return { services, isInitializing, error };
+  return { services, isInitializing, error, startupRepairReport };
 } 
diff --git a/packages/ui/src/stores/session/useSessionManager.ts b/packages/ui/src/stores/session/useSessionManager.ts
index 4ef8d8dd..87086a0b 100644
--- a/packages/ui/src/stores/session/useSessionManager.ts
+++ b/packages/ui/src/stores/session/useSessionManager.ts
@@ -39,6 +39,44 @@ export type SubModeKey =
   | 'image-image2image' // 图生图
   | 'image-multiimage' // 多图生图
 
+const SESSION_STORAGE_KEYS: Record<SubModeKey, string> = {
+  'basic-system': 'session/v1/basic-system',
+  'basic-user': 'session/v1/basic-user',
+  'pro-multi': 'session/v1/pro-multi',
+  'pro-variable': 'session/v1/pro-variable',
+  'image-text2image': 'session/v1/image-text2image',
+  'image-image2image': 'session/v1/image-image2image',
+  'image-multiimage': 'session/v1/image-multiimage',
+}
+
+const getSessionCleanupKey = (key: SubModeKey, error: unknown): string | null => {
+  if (!error || typeof error !== 'object') {
+    return null
+  }
+
+  const maybeError = error as {
+    code?: unknown
+    params?: {
+      reason?: unknown
+      key?: unknown
+    }
+  }
+
+  if (maybeError.code !== 'error.storage.read') {
+    return null
+  }
+
+  if (maybeError.params?.reason !== 'session_snapshot_too_large') {
+    return null
+  }
+
+  if (typeof maybeError.params.key === 'string' && maybeError.params.key.trim()) {
+    return maybeError.params.key
+  }
+
+  return SESSION_STORAGE_KEYS[key]
+}
+
 /**
  * 子模式读取器接口（从外部注入）
  */
@@ -275,7 +313,28 @@ export const useSessionManager = defineStore('sessionManager', () => {
           break
       }
     } catch (error) {
-      console.error(`[SessionManager] 恢复 ${key} 会话失败:`, error)
+      const cleanupKey = getSessionCleanupKey(key, error)
+      if (cleanupKey) {
+        console.info(`[SessionManager] 检测到超限会话快照，准备清理: ${cleanupKey}`)
+      } else {
+        console.error(`[SessionManager] 恢复 ${key} 会话失败:`, error)
+      }
+
+      if (!cleanupKey) {
+        return
+      }
+
+      const $services = getPiniaServices()
+      if (!$services?.preferenceService) {
+        return
+      }
+
+      try {
+        await $services.preferenceService.delete(cleanupKey)
+        console.info(`[SessionManager] 已清理超限会话快照: ${cleanupKey}`)
+      } catch (cleanupError) {
+        console.error(`[SessionManager] 清理超限会话快照失败 (${cleanupKey}):`, cleanupError)
+      }
     }
   }
 
diff --git a/packages/ui/src/utils/favorite-asset-maintenance.ts b/packages/ui/src/utils/favorite-asset-maintenance.ts
new file mode 100644
index 00000000..3131be75
--- /dev/null
+++ b/packages/ui/src/utils/favorite-asset-maintenance.ts
@@ -0,0 +1,173 @@
+import type {
+  FavoritePrompt,
+  IFavoriteManager,
+  IImageStorageService,
+} from '@prompt-optimizer/core'
+
+type FavoriteManagerForGc = Pick<
+  IFavoriteManager,
+  'getFavorites' | 'getFavorite' | 'updateFavorite' | 'deleteFavorite' | 'deleteFavorites'
+> &
+  IFavoriteManager
+
+type FavoriteAssetGcResult = {
+  deletedIds: string[]
+  referencedIds: string[]
+}
+
+const isRecord = (value: unknown): value is Record<string, unknown> =>
+  !!value && typeof value === 'object' && !Array.isArray(value)
+
+const collectStringArray = (value: unknown): string[] => {
+  if (!Array.isArray(value)) return []
+  return value
+    .map((item) => (typeof item === 'string' ? item.trim() : ''))
+    .filter(Boolean)
+}
+
+const collectFavoriteAssetIds = (
+  favorite: FavoritePrompt | null | undefined,
+): Set<string> => {
+  const assetIds = new Set<string>()
+  if (!favorite || !isRecord(favorite.metadata)) {
+    return assetIds
+  }
+
+  const media = isRecord(favorite.metadata.media) ? favorite.metadata.media : null
+  if (media) {
+    const coverAssetId = typeof media.coverAssetId === 'string' ? media.coverAssetId.trim() : ''
+    if (coverAssetId) {
+      assetIds.add(coverAssetId)
+    }
+
+    collectStringArray(media.assetIds).forEach((id) => assetIds.add(id))
+  }
+
+  const gardenSnapshot = isRecord(favorite.metadata.gardenSnapshot)
+    ? favorite.metadata.gardenSnapshot
+    : null
+  if (!gardenSnapshot || !isRecord(gardenSnapshot.assets)) {
+    return assetIds
+  }
+
+  const cover = isRecord(gardenSnapshot.assets.cover) ? gardenSnapshot.assets.cover : null
+  if (cover) {
+    const coverAssetId = typeof cover.assetId === 'string' ? cover.assetId.trim() : ''
+    if (coverAssetId) {
+      assetIds.add(coverAssetId)
+    }
+  }
+
+  const collectFromSnapshotItems = (items: unknown) => {
+    if (!Array.isArray(items)) return
+
+    items.forEach((item) => {
+      if (!isRecord(item)) return
+
+      collectStringArray(item.imageAssetIds).forEach((id) => assetIds.add(id))
+      collectStringArray(item.inputImageAssetIds).forEach((id) => assetIds.add(id))
+    })
+  }
+
+  collectFromSnapshotItems(gardenSnapshot.assets.showcases)
+  collectFromSnapshotItems(gardenSnapshot.assets.examples)
+
+  return assetIds
+}
+
+const setsAreEqual = (left: Set<string>, right: Set<string>): boolean => {
+  if (left.size !== right.size) return false
+  for (const value of left) {
+    if (!right.has(value)) return false
+  }
+  return true
+}
+
+const safeGetFavorite = async (
+  favoriteManager: FavoriteManagerForGc,
+  id: string,
+): Promise<FavoritePrompt | null> => {
+  try {
+    return await favoriteManager.getFavorite(id)
+  } catch {
+    return null
+  }
+}
+
+export const runFavoriteAssetGc = async (
+  favoriteManager: Pick<IFavoriteManager, 'getFavorites'>,
+  favoriteImageStorageService: Pick<IImageStorageService, 'listAllMetadata' | 'deleteImages'> | null | undefined,
+): Promise<FavoriteAssetGcResult> => {
+  if (!favoriteImageStorageService) {
+    return {
+      deletedIds: [],
+      referencedIds: [],
+    }
+  }
+
+  const favorites = await favoriteManager.getFavorites()
+  const referencedIds = new Set<string>()
+  favorites.forEach((favorite) => {
+    collectFavoriteAssetIds(favorite).forEach((id) => referencedIds.add(id))
+  })
+
+  const allMetadata = await favoriteImageStorageService.listAllMetadata()
+  const orphanIds = allMetadata
+    .map((metadata) => metadata.id)
+    .filter((id) => !referencedIds.has(id))
+
+  if (orphanIds.length > 0) {
+    await favoriteImageStorageService.deleteImages(orphanIds)
+  }
+
+  return {
+    deletedIds: orphanIds,
+    referencedIds: Array.from(referencedIds),
+  }
+}
+
+export const attachFavoriteAssetGc = (
+  favoriteManager: FavoriteManagerForGc,
+  favoriteImageStorageService: Pick<IImageStorageService, 'listAllMetadata' | 'deleteImages'> | null | undefined,
+): IFavoriteManager => {
+  if (!favoriteImageStorageService) {
+    return favoriteManager
+  }
+
+  return new Proxy(favoriteManager, {
+    get(target, prop, receiver) {
+      if (prop === 'deleteFavorite') {
+        return async (id: string) => {
+          await target.deleteFavorite(id)
+          await runFavoriteAssetGc(target, favoriteImageStorageService)
+        }
+      }
+
+      if (prop === 'deleteFavorites') {
+        return async (ids: string[]) => {
+          await target.deleteFavorites(ids)
+          await runFavoriteAssetGc(target, favoriteImageStorageService)
+        }
+      }
+
+      if (prop === 'updateFavorite') {
+        return async (id: string, updates: Partial<FavoritePrompt>) => {
+          const beforeFavorite = await safeGetFavorite(target, id)
+          const beforeRefs = collectFavoriteAssetIds(beforeFavorite)
+
+          await target.updateFavorite(id, updates)
+
+          const afterFavorite = await safeGetFavorite(target, id)
+          const afterRefs = collectFavoriteAssetIds(afterFavorite)
+
+          if (!setsAreEqual(beforeRefs, afterRefs)) {
+            await runFavoriteAssetGc(target, favoriteImageStorageService)
+          }
+        }
+      }
+
+      const value = Reflect.get(target, prop, receiver)
+      return typeof value === 'function' ? value.bind(target) : value
+    },
+  }) as IFavoriteManager
+}
diff --git a/packages/ui/src/utils/image-asset-storage.ts b/packages/ui/src/utils/image-asset-storage.ts
index 255c7ae5..a5409b22 100644
--- a/packages/ui/src/utils/image-asset-storage.ts
+++ b/packages/ui/src/utils/image-asset-storage.ts
@@ -25,6 +25,59 @@ const parseDataUrlPayload = (source: string): ImagePayload | null => {
   return { b64, mimeType }
 }
 
+const inferMimeTypeFromBytes = (bytes: Uint8Array): string | null => {
+  if (
+    bytes.length >= 8 &&
+    bytes[0] === 0x89 &&
+    bytes[1] === 0x50 &&
+    bytes[2] === 0x4e &&
+    bytes[3] === 0x47 &&
+    bytes[4] === 0x0d &&
+    bytes[5] === 0x0a &&
+    bytes[6] === 0x1a &&
+    bytes[7] === 0x0a
+  ) {
+    return 'image/png'
+  }
+
+  if (
+    bytes.length >= 3 &&
+    bytes[0] === 0xff &&
+    bytes[1] === 0xd8 &&
+    bytes[2] === 0xff
+  ) {
+    return 'image/jpeg'
+  }
+
+  if (
+    bytes.length >= 12 &&
+    bytes[0] === 0x52 &&
+    bytes[1] === 0x49 &&
+    bytes[2] === 0x46 &&
+    bytes[3] === 0x46 &&
+    bytes[8] === 0x57 &&
+    bytes[9] === 0x45 &&
+    bytes[10] === 0x42 &&
+    bytes[11] === 0x50
+  ) {
+    return 'image/webp'
+  }
+
+  if (
+    bytes.length >= 6 &&
+    bytes[0] === 0x47 &&
+    bytes[1] === 0x49 &&
+    bytes[2] === 0x46 &&
+    bytes[3] === 0x38 &&
+    (bytes[4] === 0x37 || bytes[4] === 0x39) &&
+    bytes[5] === 0x61
+  ) {
+    return 'image/gif'
+  }
+
+  return null
+}
+
 const fetchImagePayloadFromUrl = async (absoluteUrl: string): Promise<ImagePayload> => {
   const resp = await fetch(absoluteUrl, { method: 'GET' })
   if (!resp.ok) {
@@ -33,6 +86,13 @@ const fetchImagePayloadFromUrl = async (absoluteUrl: string): Promise<ImagePaylo
 
   const headerType = resp.headers.get('content-type')
   const mimeType = typeof headerType === 'string' ? headerType.split(';')[0].trim() : ''
+  const ab = await resp.arrayBuffer()
+  const bytes = new Uint8Array(ab)
+  const inferredMimeType = inferMimeTypeFromBytes(bytes)
+  const finalMimeType =
+    mimeType && mimeType !== 'application/octet-stream'
+      ? mimeType
+      : inferredMimeType || mimeType || 'application/octet-stream'
 
   type BufferLike = {
     from: (data: ArrayBuffer) => { toString: (encoding: 'base64') => string }
@@ -40,17 +100,15 @@ const fetchImagePayloadFromUrl = async (absoluteUrl: string): Promise<ImagePaylo
 
   const maybeBuffer = (globalThis as unknown as { Buffer?: BufferLike }).Buffer
   if (maybeBuffer && typeof maybeBuffer.from === 'function') {
-    const ab = await resp.arrayBuffer()
     const b64 = maybeBuffer.from(ab).toString('base64')
-    return { b64, mimeType: mimeType || 'application/octet-stream' }
+    return { b64, mimeType: finalMimeType }
   }
 
   if (typeof FileReader === 'undefined') {
     throw new Error('FileReader is not available to decode image payload')
   }
 
-  const blob = await resp.blob()
-  const actualMime = blob.type || mimeType || 'application/octet-stream'
+  const blob = new Blob([ab], { type: finalMimeType })
 
   const dataUrl = await new Promise<string>((resolve, reject) => {
     const reader = new FileReader()
@@ -66,7 +124,7 @@ const fetchImagePayloadFromUrl = async (absoluteUrl: string): Promise<ImagePaylo
 
   return {
     b64: parsed.b64,
-    mimeType: parsed.mimeType || actualMime,
+    mimeType: parsed.mimeType || finalMimeType,
   }
 }
 
diff --git a/packages/ui/tests/unit/composables/useAppPromptGardenImport.spec.ts b/packages/ui/tests/unit/composables/useAppPromptGardenImport.spec.ts
index 20674525..edc59b42 100644
--- a/packages/ui/tests/unit/composables/useAppPromptGardenImport.spec.ts
+++ b/packages/ui/tests/unit/composables/useAppPromptGardenImport.spec.ts
@@ -1835,6 +1835,273 @@ describe('useAppPromptGardenImport', () => {
     }
   })
 
+  it('skips auto-save to favorites when snapshot image persistence fails', async () => {
+    const { pinia } = createTestPinia()
+
+    const createReactive = (): MessageReactive => ({
+      destroy: () => {},
+    } as unknown as MessageReactive)
+    setGlobalMessageApi({
+      success: vi.fn(() => createReactive()),
+      error: vi.fn(() => createReactive()),
+      warning: vi.fn(() => createReactive()),
+      info: vi.fn(() => createReactive()),
+    })
+
+    const basicSystemSession = useBasicSystemSession(pinia)
+    const basicUserSession = useBasicUserSession(pinia)
+    const proMultiMessageSession = useProMultiMessageSession(pinia)
+    const proVariableSession = useProVariableSession(pinia)
+    const imageText2ImageSession = useImageText2ImageSession(pinia)
+    const imageImage2ImageSession = useImageImage2ImageSession(pinia)
+
+    const optimizerCurrentVersions = ref<PromptRecordChain['versions']>([])
+    const hasRestoredInitialState = ref(false)
+    const isLoadingExternalData = ref(false)
+
+    const query: LocationQuery = {
+      importCode: 'NB-SAVE-FAIL-001',
+      saveToFavorites: '1',
+    }
+
+    const currentRoute = ref<RouteLocationNormalizedLoaded>(makeRoute('/basic/system', query))
+
+    let replaceResolve: (() => void) | undefined
+    const replaceDone = new Promise<void>((resolve) => {
+      replaceResolve = resolve
+    })
+
+    const push: Router['push'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      return undefined
+    })
+
+    const replace: Router['replace'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      replaceResolve?.()
+      return undefined
+    })
+
+    const router: Pick<Router, 'currentRoute' | 'push' | 'replace'> = {
+      currentRoute,
+      push,
+      replace,
+    }
+
+    const favoriteManager = {
+      getFavorites: vi.fn(async (): Promise<FavoritePrompt[]> => []),
+      addFavorite: vi.fn(async (
+        _favorite: Omit<FavoritePrompt, 'id' | 'createdAt' | 'updatedAt' | 'useCount'>
+      ) => 'fav-new'),
+      updateFavorite: vi.fn(async (_id: string, _updates: Partial<FavoritePrompt>) => {}),
+    }
+
+    const imageStorageService = {
+      getMetadata: vi.fn(async () => null),
+      saveImage: vi.fn(async () => {
+        throw new Error('boom')
+      }),
+    } as any
+
+    const fetchMock = vi.fn<
+      (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>
+    >(async () => {
+      return new Response(
+        JSON.stringify({
+          id: 'prompt-asset-fail-1',
+          importCode: 'NB-SAVE-FAIL-001',
+          schema: 'prompt-garden.prompt.v1',
+          schemaVersion: 1,
+          optimizerTarget: { subModeKey: 'basic-system' },
+          prompt: { format: 'text', text: 'PROMPT WITH ASSET FAILURE' },
+          variables: [],
+          assets: {
+            cover: {
+              url: '/prompt-assets/cover.png',
+            },
+            showcases: [
+              {
+                id: 'show-1',
+                images: ['/prompt-assets/show-1.png'],
+              },
+            ],
+          },
+        }),
+        {
+          status: 200,
+          headers: { 'content-type': 'application/json' },
+        }
+      )
+    })
+    vi.stubGlobal('fetch', fetchMock)
+
+    const scope = effectScope()
+    try {
+      scope.run(() => {
+        useAppPromptGardenImport({
+          router,
+          hasRestoredInitialState,
+          isLoadingExternalData,
+          gardenBaseUrl: 'http://garden.local',
+          basicSystemSession,
+          basicUserSession,
+          proMultiMessageSession,
+          proVariableSession,
+          imageText2ImageSession,
+          imageImage2ImageSession,
+          getFavoriteManager: () => favoriteManager,
+          getFavoriteImageStorageService: () => imageStorageService,
+          optimizerCurrentVersions,
+        })
+      })
+
+      hasRestoredInitialState.value = true
+
+      await replaceDone
+      await waitForCondition(() => isLoadingExternalData.value === false)
+
+      expect(favoriteManager.getFavorites).not.toHaveBeenCalled()
+      expect(favoriteManager.addFavorite).not.toHaveBeenCalled()
+      expect(favoriteManager.updateFavorite).not.toHaveBeenCalled()
+    } finally {
+      scope.stop()
+    }
+  })
+
+  it('opens save-favorite dialog without media fallback when snapshot image persistence fails', async () => {
+    const { pinia } = createTestPinia()
+
+    const createReactive = (): MessageReactive => ({
+      destroy: () => {},
+    } as unknown as MessageReactive)
+    setGlobalMessageApi({
+      success: vi.fn(() => createReactive()),
+      error: vi.fn(() => createReactive()),
+      warning: vi.fn(() => createReactive()),
+      info: vi.fn(() => createReactive()),
+    })
+
+    const basicSystemSession = useBasicSystemSession(pinia)
+    const basicUserSession = useBasicUserSession(pinia)
+    const proMultiMessageSession = useProMultiMessageSession(pinia)
+    const proVariableSession = useProVariableSession(pinia)
+    const imageText2ImageSession = useImageText2ImageSession(pinia)
+    const imageImage2ImageSession = useImageImage2ImageSession(pinia)
+
+    const optimizerCurrentVersions = ref<PromptRecordChain['versions']>([])
+    const hasRestoredInitialState = ref(false)
+    const isLoadingExternalData = ref(false)
+
+    const query: LocationQuery = {
+      importCode: 'NB-CONFIRM-FAIL-001',
+      saveToFavorites: 'confirm',
+    }
+
+    const currentRoute = ref<RouteLocationNormalizedLoaded>(makeRoute('/basic/system', query))
+
+    let replaceResolve: (() => void) | undefined
+    const replaceDone = new Promise<void>((resolve) => {
+      replaceResolve = resolve
+    })
+
+    const push: Router['push'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      return undefined
+    })
+
+    const replace: Router['replace'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      replaceResolve?.()
+      return undefined
+    })
+
+    const router: Pick<Router, 'currentRoute' | 'push' | 'replace'> = {
+      currentRoute,
+      push,
+      replace,
+    }
+
+    const openSaveFavoriteDialog = vi.fn()
+    const imageStorageService = {
+      getMetadata: vi.fn(async () => null),
+      saveImage: vi.fn(async () => {
+        throw new Error('boom')
+      }),
+    } as any
+
+    const fetchMock = vi.fn<
+      (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>
+    >(async () => {
+      return new Response(
+        JSON.stringify({
+          id: 'prompt-confirm-fail-1',
+          importCode: 'NB-CONFIRM-FAIL-001',
+          schema: 'prompt-garden.prompt.v1',
+          schemaVersion: 1,
+          optimizerTarget: { subModeKey: 'basic-system' },
+          prompt: { format: 'text', text: 'CONFIRM CONTENT WITH IMAGE' },
+          variables: [],
+          assets: {
+            cover: {
+              url: '/prompt-assets/cover.png',
+            },
+            showcases: [
+              {
+                id: 'show-1',
+                images: ['/prompt-assets/show-1.png'],
+              },
+            ],
+          },
+          meta: {
+            title: 'Confirm Prompt Title',
+          },
+        }),
+        {
+          status: 200,
+          headers: { 'content-type': 'application/json' },
+        }
+      )
+    })
+    vi.stubGlobal('fetch', fetchMock)
+
+    const scope = effectScope()
+    try {
+      scope.run(() => {
+        useAppPromptGardenImport({
+          router,
+          hasRestoredInitialState,
+          isLoadingExternalData,
+          gardenBaseUrl: 'http://garden.local',
+          basicSystemSession,
+          basicUserSession,
+          proMultiMessageSession,
+          proVariableSession,
+          imageText2ImageSession,
+          imageImage2ImageSession,
+          getFavoriteImageStorageService: () => imageStorageService,
+          openSaveFavoriteDialog,
+          optimizerCurrentVersions,
+        })
+      })
+
+      hasRestoredInitialState.value = true
+
+      await replaceDone
+      await waitForCondition(() => isLoadingExternalData.value === false)
+
+      expect(openSaveFavoriteDialog).toHaveBeenCalledTimes(1)
+      const savedArg = openSaveFavoriteDialog.mock.calls[0]?.[0] as {
+        prefill?: {
+          metadata?: Record<string, unknown>
+        }
+      }
+
+      expect(savedArg.prefill?.metadata?.media).toBeUndefined()
+    } finally {
+      scope.stop()
+    }
+  })
+
   it('does not auto-save when saveToFavorites flag is absent', async () => {
     const { pinia } = createTestPinia()
 
@@ -2108,4 +2375,127 @@ describe('useAppPromptGardenImport', () => {
       scope.stop()
     }
   })
+
+  it('shows a warning when Prompt Garden auto-save to favorites fails', async () => {
+    const { pinia } = createTestPinia()
+
+    const createReactive = (): MessageReactive => ({
+      destroy: () => {},
+    } as unknown as MessageReactive)
+    const successMock = vi.fn(() => createReactive())
+    const errorMock = vi.fn(() => createReactive())
+    const warningMock = vi.fn(() => createReactive())
+    setGlobalMessageApi({
+      success: successMock,
+      error: errorMock,
+      warning: warningMock,
+      info: vi.fn(() => createReactive()),
+    })
+
+    const basicSystemSession = useBasicSystemSession(pinia)
+    const basicUserSession = useBasicUserSession(pinia)
+    const proMultiMessageSession = useProMultiMessageSession(pinia)
+    const proVariableSession = useProVariableSession(pinia)
+    const imageText2ImageSession = useImageText2ImageSession(pinia)
+    const imageImage2ImageSession = useImageImage2ImageSession(pinia)
+
+    const optimizerCurrentVersions = ref<PromptRecordChain['versions']>([])
+    const hasRestoredInitialState = ref(false)
+    const isLoadingExternalData = ref(false)
+
+    const query: LocationQuery = {
+      importCode: 'NB-AUTO-SAVE-FAIL-001',
+      saveToFavorites: 'true',
+    }
+
+    const currentRoute = ref<RouteLocationNormalizedLoaded>(makeRoute('/basic/system', query))
+
+    let replaceResolve: (() => void) | undefined
+    const replaceDone = new Promise<void>((resolve) => {
+      replaceResolve = resolve
+    })
+
+    const push: Router['push'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      return undefined
+    })
+
+    const replace: Router['replace'] = vi.fn(async (to) => {
+      applyNavigation(currentRoute, to)
+      replaceResolve?.()
+      return undefined
+    })
+
+    const router: Pick<Router, 'currentRoute' | 'push' | 'replace'> = {
+      currentRoute,
+      push,
+      replace,
+    }
+
+    const favoriteManager = {
+      getFavorites: vi.fn(async (): Promise<FavoritePrompt[]> => []),
+      addFavorite: vi.fn(async () => {
+        throw new Error('favorites payload exceeds hard limit')
+      }),
+      updateFavorite: vi.fn(async (_id: string, _updates: Partial<FavoritePrompt>) => {}),
+    }
+
+    const fetchMock = vi.fn<
+      (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>
+    >(async () => {
+      return new Response(
+        JSON.stringify({
+          schema: 'prompt-garden.prompt.v1',
+          schemaVersion: 1,
+          optimizerTarget: { subModeKey: 'basic-system' },
+          prompt: { format: 'text', text: 'AUTO SAVE FAIL PROMPT' },
+          variables: [],
+          meta: {
+            title: 'Auto Save Fail Prompt',
+          },
+        }),
+        {
+          status: 200,
+          headers: { 'content-type': 'application/json' },
+        },
+      )
+    })
+    vi.stubGlobal('fetch', fetchMock)
+
+    const scope = effectScope()
+    try {
+      scope.run(() => {
+        useAppPromptGardenImport({
+          router,
+          hasRestoredInitialState,
+          isLoadingExternalData,
+          gardenBaseUrl: 'http://garden.local',
+          basicSystemSession,
+          basicUserSession,
+          proMultiMessageSession,
+          proVariableSession,
+          imageText2ImageSession,
+          imageImage2ImageSession,
+          getFavoriteManager: () => favoriteManager,
+          optimizerCurrentVersions,
+        })
+      })
+
+      hasRestoredInitialState.value = true
+
+      await replaceDone
+      await waitForCondition(() => isLoadingExternalData.value === false)
+
+      expect(favoriteManager.getFavorites).toHaveBeenCalledTimes(1)
+      expect(favoriteManager.addFavorite).toHaveBeenCalledTimes(1)
+      expect(warningMock).toHaveBeenCalledTimes(1)
+      expect(warningMock.mock.calls[0]?.[0]).toEqual(
+        expect.stringContaining('收藏'),
+      )
+      expect(errorMock).not.toHaveBeenCalled()
+      expect(successMock).toHaveBeenCalled()
+    } finally {
+      scope.stop()
+    }
+  })
 })
diff --git a/packages/ui/tests/unit/stores/session/session-manager.spec.ts b/packages/ui/tests/unit/stores/session/session-manager.spec.ts
new file mode 100644
index 00000000..04611e8b
--- /dev/null
+++ b/packages/ui/tests/unit/stores/session/session-manager.spec.ts
@@ -0,0 +1,39 @@
+import { describe, it, expect, vi } from 'vitest'
+
+import { createTestPinia, createPreferenceServiceStub } from '../../../utils/pinia-test-helpers'
+import { useSessionManager } from '../../../../src/stores/session/useSessionManager'
+
+describe('SessionManager', () => {
+  it('cleans only the oversized session key when restore fails with session snapshot overflow', async () => {
+    const deleteMock = vi.fn(async () => {})
+
+    const { pinia, services } = createTestPinia({
+      preferenceService: createPreferenceServiceStub({
+        get: vi.fn(async () => {
+          throw {
+            code: 'error.storage.read',
+            params: {
+              reason: 'session_snapshot_too_large',
+              key: 'session/v1/image-multiimage',
+            },
+          }
+        }),
+        delete: deleteMock,
+      }),
+      imageStorageService: {
+        getImage: vi.fn(async () => null),
+      } as any,
+    })
+
+    const manager = useSessionManager(pinia)
+
+    await manager.restoreSubModeSession('image-multiimage')
+
+    expect(deleteMock).toHaveBeenCalledTimes(1)
+    expect(deleteMock).toHaveBeenCalledWith('session/v1/image-multiimage')
+    expect(services.preferenceService.get).toHaveBeenCalledWith(
+      'session/v1/image-multiimage',
+      null,
+    )
+  })
+})
diff --git a/packages/ui/tests/unit/utils/favorite-asset-maintenance.spec.ts b/packages/ui/tests/unit/utils/favorite-asset-maintenance.spec.ts
new file mode 100644
index 00000000..f842064b
--- /dev/null
+++ b/packages/ui/tests/unit/utils/favorite-asset-maintenance.spec.ts
@@ -0,0 +1,190 @@
+import { describe, it, expect, vi } from 'vitest'
+
+import {
+  attachFavoriteAssetGc,
+  runFavoriteAssetGc,
+} from '../../../src/utils/favorite-asset-maintenance'
+
+describe('favoriteAssetMaintenance', () => {
+  it('deletes orphaned assets from the favorite image store', async () => {
+    const favoriteManager = {
+      getFavorites: vi.fn(async () => [
+        {
+          id: 'fav-1',
+          metadata: {
+            media: {
+              coverAssetId: 'cover-1',
+              assetIds: ['asset-1'],
+            },
+            gardenSnapshot: {
+              assets: {
+                showcases: [{ imageAssetIds: ['gallery-1'] }],
+                examples: [{ inputImageAssetIds: ['input-1'] }],
+              },
+            },
+          },
+        },
+      ]),
+    }
+
+    const favoriteImageStorageService = {
+      listAllMetadata: vi.fn(async () => [
+        { id: 'cover-1' },
+        { id: 'asset-1' },
+        { id: 'gallery-1' },
+        { id: 'input-1' },
+        { id: 'orphan-1' },
+      ]),
+      deleteImages: vi.fn(async (_ids: string[]) => {}),
+    }
+
+    const result = await runFavoriteAssetGc(
+      favoriteManager as any,
+      favoriteImageStorageService as any,
+    )
+
+    expect(favoriteImageStorageService.deleteImages).toHaveBeenCalledWith(['orphan-1'])
+    expect(result.deletedIds).toEqual(['orphan-1'])
+  })
+
+  it('runs GC after deleting a favorite and keeps assets still referenced by siblings', async () => {
+    const favorites = [
+      {
+        id: 'fav-1',
+        metadata: {
+          media: {
+            assetIds: ['shared-asset', 'soon-orphaned'],
+          },
+        },
+      },
+      {
+        id: 'fav-2',
+        metadata: {
+          media: {
+            assetIds: ['shared-asset'],
+          },
+        },
+      },
+    ]
+
+    const favoriteManager = {
+      addFavorite: vi.fn(),
+      getFavorites: vi.fn(async () => favorites),
+      getFavorite: vi.fn(async (id: string) => favorites.find((favorite) => favorite.id === id) || null),
+      updateFavorite: vi.fn(),
+      deleteFavorite: vi.fn(async (id: string) => {
+        const index = favorites.findIndex((favorite) => favorite.id === id)
+        if (index >= 0) {
+          favorites.splice(index, 1)
+        }
+      }),
+      deleteFavorites: vi.fn(),
+      incrementUseCount: vi.fn(),
+      getCategories: vi.fn(),
+      addCategory: vi.fn(),
+      updateCategory: vi.fn(),
+      deleteCategory: vi.fn(),
+      getStats: vi.fn(),
+      searchFavorites: vi.fn(),
+      exportFavorites: vi.fn(),
+      importFavorites: vi.fn(),
+      getAllTags: vi.fn(),
+      addTag: vi.fn(),
+      renameTag: vi.fn(),
+      mergeTags: vi.fn(),
+      deleteTag: vi.fn(),
+      reorderCategories: vi.fn(),
+      getCategoryUsage: vi.fn(),
+      ensureDefaultCategories: vi.fn(),
+    }
+
+    const favoriteImageStorageService = {
+      listAllMetadata: vi.fn(async () => [
+        { id: 'shared-asset' },
+        { id: 'soon-orphaned' },
+      ]),
+      deleteImages: vi.fn(async (_ids: string[]) => {}),
+    }
+
+    const guardedManager = attachFavoriteAssetGc(
+      favoriteManager as any,
+      favoriteImageStorageService as any,
+    )
+
+    await guardedManager.deleteFavorite('fav-1')
+
+    expect(favoriteManager.deleteFavorite).toHaveBeenCalledWith('fav-1')
+    expect(favoriteImageStorageService.deleteImages).toHaveBeenCalledWith(['soon-orphaned'])
+  })
+
+  it('runs GC after updating a favorite when image references change', async () => {
+    const favorites = [
+      {
+        id: 'fav-1',
+        metadata: {
+          media: {
+            assetIds: ['old-asset'],
+          },
+        },
+      },
+    ]
+
+    const favoriteManager = {
+      addFavorite: vi.fn(),
+      getFavorites: vi.fn(async () => favorites),
+      getFavorite: vi.fn(async (id: string) => favorites.find((favorite) => favorite.id === id) || null),
+      updateFavorite: vi.fn(async (id: string, updates: Record<string, unknown>) => {
+        const index = favorites.findIndex((favorite) => favorite.id === id)
+        if (index >= 0) {
+          favorites[index] = {
+            ...favorites[index],
+            ...updates,
+          }
+        }
+      }),
+      deleteFavorite: vi.fn(),
+      deleteFavorites: vi.fn(),
+      incrementUseCount: vi.fn(),
+      getCategories: vi.fn(),
+      addCategory: vi.fn(),
+      updateCategory: vi.fn(),
+      deleteCategory: vi.fn(),
+      getStats: vi.fn(),
+      searchFavorites: vi.fn(),
+      exportFavorites: vi.fn(),
+      importFavorites: vi.fn(),
+      getAllTags: vi.fn(),
+      addTag: vi.fn(),
+      renameTag: vi.fn(),
+      mergeTags: vi.fn(),
+      deleteTag: vi.fn(),
+      reorderCategories: vi.fn(),
+      getCategoryUsage: vi.fn(),
+      ensureDefaultCategories: vi.fn(),
+    }
+
+    const favoriteImageStorageService = {
+      listAllMetadata: vi.fn(async () => [
+        { id: 'old-asset' },
+        { id: 'new-asset' },
+      ]),
+      deleteImages: vi.fn(async (_ids: string[]) => {}),
+    }
+
+    const guardedManager = attachFavoriteAssetGc(
+      favoriteManager as any,
+      favoriteImageStorageService as any,
+    )
+
+    await guardedManager.updateFavorite('fav-1', {
+      metadata: {
+        media: {
+          assetIds: ['new-asset'],
+        },
+      },
+    } as any)
+
+    expect(favoriteManager.updateFavorite).toHaveBeenCalled()
+    expect(favoriteImageStorageService.deleteImages).toHaveBeenCalledWith(['old-asset'])
+  })
+})
diff --git a/packages/ui/tests/unit/utils/image-asset-storage.spec.ts b/packages/ui/tests/unit/utils/image-asset-storage.spec.ts
new file mode 100644
index 00000000..86043755
--- /dev/null
+++ b/packages/ui/tests/unit/utils/image-asset-storage.spec.ts
@@ -0,0 +1,39 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+import { normalizeImageSourceToPayload } from '../../../src/utils/image-asset-storage'
+
+describe('image asset storage utilities', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals()
+    vi.restoreAllMocks()
+  })
+
+  it('infers image mime type from PNG bytes when the remote url responds as application/octet-stream', async () => {
+    const pngBytes = Uint8Array.from([
+      0x89, 0x50, 0x4e, 0x47,
+      0x0d, 0x0a, 0x1a, 0x0a,
+      0x00, 0x00, 0x00, 0x0d,
+      0x49, 0x48, 0x44, 0x52,
+    ])
+
+    vi.stubGlobal(
+      'fetch',
+      vi.fn(async () => ({
+        ok: true,
+        headers: {
+          get: vi.fn((name: string) =>
+            name.toLowerCase() === 'content-type' ? 'application/octet-stream' : null
+          ),
+        },
+        arrayBuffer: async () => pngBytes.buffer,
+      }))
+    )
+
+    const payload = await normalizeImageSourceToPayload('https://example.com/generated-image')
+
+    expect(payload).toMatchObject({
+      mimeType: 'image/png',
+      b64: Buffer.from(pngBytes).toString('base64'),
+    })
+  })
+})