feat: add customizable download sources with automatic fallback

- support built-in and user-defined GitHub mirror sources
- add a modal for managing custom HTTPS mirror prefixes
- automatically switch sources when version checks fail
- persist the working source and sync the selector in real time
- update translations, configuration migration, and source tests

src/i18n/ja.ts

@@ -973,11 +973,23 @@ export const jaOverrides = {
   'kernel.versions.noBundled': 'このリリースには組み込みコアが含まれていません',
   'kernel.versions.offlineInstall': 'オフラインインストール',
   'kernel.versions.downloadSource': 'ダウンロード元を切り替える',
-  'kernel.versions.downloadSourceHint': 'ソフトウェアとコアの更新確認・ダウンロードでは選択した経路を優先し、失敗時は他の利用可能なソースに切り替えます。ミラープロキシは第三者が提供します。',
+  'kernel.versions.downloadSourceHint': '組み込み経路を選択するか、カスタム HTTPS ミラープレフィックスを追加できます。確認失敗時は自動的に切り替えます。ミラープロキシは第三者が提供します。',
   'kernel.versions.source.github': 'GitHub 公式',
   'kernel.versions.source.gitcode': 'GitCode 中国向けミラー',
   'kernel.versions.source.ghProxy': 'GitHub ミラー · gh-proxy.com',
   'kernel.versions.source.ghFast': 'GitHub ミラー · ghfast.top',
+  'kernel.versions.source.custom': 'カスタムミラー',
+  'kernel.versions.customMirrorPlaceholder': 'ミラープレフィックス（例: https://mirror.example.com/）',
+  'kernel.versions.customMirrorAdd': 'カスタムソースを追加',
+  'kernel.versions.customMirrorDialogTitle': 'カスタムダウンロード元を追加',
+  'kernel.versions.customMirrorDialogDescription': 'GitHub ミラープロキシの HTTPS プレフィックスを入力してください。ダウンロード時に元の GitHub URL を末尾へ追加します。',
+  'kernel.versions.customMirrorConfirm': '追加して切り替え',
+  'kernel.versions.customMirrorAdded': 'カスタムミラーを追加して切り替えました',
+  'kernel.versions.customMirrorAddFailed': 'ミラーの追加に失敗しました: {error}',
+  'kernel.versions.customMirrorRemove': 'カスタムソースを削除',
+  'kernel.versions.customMirrorSaved': '追加済みのカスタムソース',
+  'kernel.versions.customMirrorRemoved': 'カスタムミラーを削除しました',
+  'kernel.versions.customMirrorRemoveFailed': 'ミラーの削除に失敗しました: {error}',
   'kernel.versions.gitcodeUnavailable': 'このビルドには完全な GitCode ミラー設定が含まれていません。',
   'kernel.versions.gitcodeSaveFailed': 'ダウンロード元の切り替えに失敗しました: {error}',
   'kernel.access.firstKey': '最初のキー',

src/i18n/locales/en.ts

@@ -973,11 +973,23 @@ export const en: Record<MessageKey, string> = {
   'kernel.versions.noBundled': 'This release does not include a bundled core',
   'kernel.versions.offlineInstall': 'Offline Install',
   'kernel.versions.downloadSource': 'Switch Download Source',
-  'kernel.versions.downloadSourceHint': 'Software and core update checks and downloads prefer the selected channel, then fall back to other available sources. Mirror proxies are third-party services.',
+  'kernel.versions.downloadSourceHint': 'Choose a built-in channel or add a custom HTTPS mirror prefix. Failed checks automatically fall back. Mirror proxies are third-party services.',
   'kernel.versions.source.github': 'Official GitHub',
   'kernel.versions.source.gitcode': 'GitCode China Mirror',
   'kernel.versions.source.ghProxy': 'GitHub Mirror · gh-proxy.com',
   'kernel.versions.source.ghFast': 'GitHub Mirror · ghfast.top',
+  'kernel.versions.source.custom': 'Custom Mirror',
+  'kernel.versions.customMirrorPlaceholder': 'Mirror prefix, e.g. https://mirror.example.com/',
+  'kernel.versions.customMirrorAdd': 'Add Custom Source',
+  'kernel.versions.customMirrorDialogTitle': 'Add Custom Download Source',
+  'kernel.versions.customMirrorDialogDescription': 'Enter the HTTPS prefix of a GitHub mirror proxy. The original GitHub URL is appended when downloading.',
+  'kernel.versions.customMirrorConfirm': 'Add and Switch',
+  'kernel.versions.customMirrorAdded': 'Custom mirror added and selected',
+  'kernel.versions.customMirrorAddFailed': 'Failed to add mirror: {error}',
+  'kernel.versions.customMirrorRemove': 'Remove custom source',
+  'kernel.versions.customMirrorSaved': 'Added custom sources',
+  'kernel.versions.customMirrorRemoved': 'Custom mirror removed',
+  'kernel.versions.customMirrorRemoveFailed': 'Failed to remove mirror: {error}',
   'kernel.versions.gitcodeUnavailable': 'This build does not include complete GitCode mirror configuration.',
   'kernel.versions.gitcodeSaveFailed': 'Failed to switch download source: {error}',
   'kernel.access.firstKey': 'First key',

src/i18n/locales/zh-CN.ts

@@ -971,11 +971,23 @@ export const zhCN = {
   'kernel.versions.noBundled': '当前发行包未包含内置内核',
   'kernel.versions.offlineInstall': '离线安装',
   'kernel.versions.downloadSource': '切换下载源',
-  'kernel.versions.downloadSourceHint': '软件和内核的版本检查及下载将优先使用所选渠道，失败时自动回退到其他可用源。镜像代理由第三方提供。',
+  'kernel.versions.downloadSourceHint': '可选择内置渠道或添加自定义 HTTPS 镜像前缀；检测失败时会自动回退。镜像代理由第三方提供。',
   'kernel.versions.source.github': 'GitHub 官方源',
   'kernel.versions.source.gitcode': 'GitCode 国内源',
   'kernel.versions.source.ghProxy': 'GitHub 镜像 · gh-proxy.com',
   'kernel.versions.source.ghFast': 'GitHub 镜像 · ghfast.top',
+  'kernel.versions.source.custom': '自定义镜像',
+  'kernel.versions.customMirrorPlaceholder': '镜像前缀，例如 https://mirror.example.com/',
+  'kernel.versions.customMirrorAdd': '添加自定义源',
+  'kernel.versions.customMirrorDialogTitle': '添加自定义下载源',
+  'kernel.versions.customMirrorDialogDescription': '填写 GitHub 镜像代理的 HTTPS 前缀。下载时会在该地址后拼接原始 GitHub URL。',
+  'kernel.versions.customMirrorConfirm': '添加并切换',
+  'kernel.versions.customMirrorAdded': '已添加并切换到自定义镜像',
+  'kernel.versions.customMirrorAddFailed': '添加镜像失败：{error}',
+  'kernel.versions.customMirrorRemove': '删除自定义源',
+  'kernel.versions.customMirrorSaved': '已添加的自定义源',
+  'kernel.versions.customMirrorRemoved': '已删除自定义镜像',
+  'kernel.versions.customMirrorRemoveFailed': '删除镜像失败：{error}',
   'kernel.versions.gitcodeUnavailable': '当前构建未配置完整的 GitCode 镜像源。',
   'kernel.versions.gitcodeSaveFailed': '切换下载源失败：{error}',
   'kernel.access.firstKey': '第一个密钥',

src/pages/VersionManagementPage.tsx

@@ -10,6 +10,7 @@ import {
   Info,
   RefreshCw,
   RotateCcw,
+  Trash2,
 } from 'lucide-react';
 import { useCoreRuntime } from '../coreRuntime';
 import { useI18n } from '../i18n';
@@ -41,18 +42,27 @@ export type CoreInstallTask = {
 export type VersionSourceSettings = {
   source: VersionDownloadSource;
   gitcodeAvailable: boolean;
+  customMirrors: string[];
 };
 
-export type VersionDownloadSource = 'github' | 'gitcode' | 'gh-proxy' | 'gh-fast';
+export type VersionDownloadSource = string;
 
 function downloadSourceLabel(source: VersionDownloadSource, t: ReturnType<typeof useI18n>['t']) {
-  const keys = {
+  const keys: Record<string, Parameters<typeof t>[0]> = {
     github: 'kernel.versions.source.github',
     gitcode: 'kernel.versions.source.gitcode',
     'gh-proxy': 'kernel.versions.source.ghProxy',
     'gh-fast': 'kernel.versions.source.ghFast',
-  } as const;
-  return t(keys[source]);
+  };
+  if (source.startsWith('custom:')) {
+    const url = source.slice('custom:'.length);
+    try {
+      return `${t('kernel.versions.source.custom')} · ${new URL(url).host}`;
+    } catch {
+      return t('kernel.versions.source.custom');
+    }
+  }
+  return t(keys[source] ?? 'kernel.versions.source.github');
 }
 
 export type MessageType = 'info' | 'success' | 'error';
@@ -131,6 +141,8 @@ export function VersionManagementPage() {
   const [versionSource, setVersionSource] = useState<VersionSourceSettings | null>(null);
   const [versionSourceSaving, setVersionSourceSaving] = useState(false);
   const [versionSourceError, setVersionSourceError] = useState('');
+  const [customMirrorDraft, setCustomMirrorDraft] = useState('');
+  const [customMirrorDialogOpen, setCustomMirrorDialogOpen] = useState(false);
 
   const [toastNotice, setToastNotice] = useState<{
     message: string;
@@ -138,6 +150,7 @@ export function VersionManagementPage() {
   } | null>(null);
 
   const installDialogRef = useRef<HTMLDivElement>(null);
+  const customMirrorInputRef = useRef<HTMLInputElement>(null);
   const latestCheckEpochRef = useRef(0);
   const toastTimerRef = useRef<number | null>(null);
 
@@ -242,6 +255,52 @@ export function VersionManagementPage() {
     }
   };
 
+  const addCustomMirror = async () => {
+    const url = customMirrorDraft.trim();
+    if (!url) return;
+    setVersionSourceSaving(true);
+    setVersionSourceError('');
+    try {
+      const settings = await invoke<VersionSourceSettings>('add_custom_download_mirror', { url });
+      setVersionSource(settings);
+      setCustomMirrorDraft('');
+      setCustomMirrorDialogOpen(false);
+      cachedLatest = null;
+      cachedLatestError = '';
+      setLatest(null);
+      showToast(t('kernel.versions.customMirrorAdded'), 'success');
+      await Promise.allSettled([checkAppUpdate(), checkLatest(true)]);
+    } catch (error) {
+      const message = t('kernel.versions.customMirrorAddFailed', { error: String(error) });
+      setVersionSourceError(message);
+      showToast(message, 'error');
+    } finally {
+      setVersionSourceSaving(false);
+    }
+  };
+
+  const removeCustomMirror = async (url: string) => {
+    const wasSelected = versionSource?.source === `custom:${url}`;
+    setVersionSourceSaving(true);
+    setVersionSourceError('');
+    try {
+      const settings = await invoke<VersionSourceSettings>('remove_custom_download_mirror', {
+        url,
+      });
+      setVersionSource(settings);
+      showToast(t('kernel.versions.customMirrorRemoved'), 'success');
+      if (wasSelected) {
+        await Promise.allSettled([checkAppUpdate(), checkLatest(true)]);
+      }
+    } catch (error) {
+      const message = t('kernel.versions.customMirrorRemoveFailed', { error: String(error) });
+      setVersionSourceError(message);
+      showToast(message, 'error');
+    } finally {
+      setVersionSourceSaving(false);
+    }
+  };
+
   const installVersion = async (version: string) => {
     setInstalling(true);
     setCancellingInstall(false);
@@ -403,6 +462,25 @@ export function VersionManagementPage() {
     };
   }, [installDialogOpen]);
 
+  useEffect(() => {
+    if (!customMirrorDialogOpen) return;
+
+    const previousOverflow = document.body.style.overflow;
+    document.body.style.overflow = 'hidden';
+    window.setTimeout(() => customMirrorInputRef.current?.focus(), 0);
+
+    const closeOnEscape = (event: KeyboardEvent) => {
+      if (event.key === 'Escape' && !versionSourceSaving) {
+        setCustomMirrorDialogOpen(false);
+      }
+    };
+    document.addEventListener('keydown', closeOnEscape);
+    return () => {
+      document.body.style.overflow = previousOverflow;
+      document.removeEventListener('keydown', closeOnEscape);
+    };
+  }, [customMirrorDialogOpen, versionSourceSaving]);
+
   // Derived state calculations
   const latestVersion = latest?.version ?? '';
   const currentVersion = coreStatus?.currentVersion ?? '';
@@ -531,8 +609,24 @@ export function VersionManagementPage() {
                 </option>
                 <option value="gh-proxy">{t('kernel.versions.source.ghProxy')}</option>
                 <option value="gh-fast">{t('kernel.versions.source.ghFast')}</option>
+                {versionSource?.customMirrors.map((url) => (
+                  <option key={url} value={`custom:${url}`}>
+                    {downloadSourceLabel(`custom:${url}`, t)}
+                  </option>
+                ))}
               </select>
             </label>
+            <button
+              type="button"
+              className="version-source-add-button"
+              disabled={versionSourceSaving || appUpdateTask.running || installing}
+              onClick={() => {
+                setVersionSourceError('');
+                setCustomMirrorDialogOpen(true);
+              }}
+            >
+              <span>{t('kernel.versions.customMirrorAdd')}</span>
+            </button>
           </div>
         </div>
 
@@ -680,6 +774,81 @@ export function VersionManagementPage() {
         </div>
       </section>
 
+      {customMirrorDialogOpen ? (
+        <div className="install-dialog-backdrop custom-mirror-dialog-backdrop">
+          <form
+            className="install-dialog app-update-dialog custom-mirror-dialog"
+            role="dialog"
+            aria-modal="true"
+            aria-labelledby="custom-mirror-dialog-title"
+            onSubmit={(event) => {
+              event.preventDefault();
+              void addCustomMirror();
+            }}
+          >
+            <div className="install-dialog-heading">
+              <span>{t('kernel.versions.downloadSource')}</span>
+              <h2 id="custom-mirror-dialog-title">{t('kernel.versions.customMirrorDialogTitle')}</h2>
+            </div>
+            <p className="custom-mirror-dialog-description">
+              {t('kernel.versions.customMirrorDialogDescription')}
+            </p>
+            <input
+              ref={customMirrorInputRef}
+              type="url"
+              value={customMirrorDraft}
+              disabled={versionSourceSaving}
+              placeholder={t('kernel.versions.customMirrorPlaceholder')}
+              aria-label={t('kernel.versions.customMirrorPlaceholder')}
+              onChange={(event) => setCustomMirrorDraft(event.currentTarget.value)}
+            />
+            {versionSourceError ? (
+              <span className="custom-mirror-dialog-error" role="alert">{versionSourceError}</span>
+            ) : null}
+            {versionSource?.customMirrors.length ? (
+              <div className="custom-mirror-dialog-list">
+                <span>{t('kernel.versions.customMirrorSaved')}</span>
+                {versionSource.customMirrors.map((url) => (
+                  <div key={url}>
+                    <span title={url}>{url}</span>
+                    <button
+                      type="button"
+                      disabled={versionSourceSaving}
+                      title={t('kernel.versions.customMirrorRemove')}
+                      aria-label={t('kernel.versions.customMirrorRemove')}
+                      onClick={() => void removeCustomMirror(url)}
+                    >
+                      <Trash2 size={15} aria-hidden="true" />
+                    </button>
+                  </div>
+                ))}
+              </div>
+            ) : null}
+            <div className="app-update-dialog-actions">
+              <button
+                type="button"
+                className="secondary-button"
+                disabled={versionSourceSaving}
+                onClick={() => {
+                  setCustomMirrorDialogOpen(false);
+                  setCustomMirrorDraft('');
+                  setVersionSourceError('');
+                }}
+              >
+                {t('common.cancel')}
+              </button>
+              <button
+                type="submit"
+                className="secondary-button"
+                disabled={!customMirrorDraft.trim() || versionSourceSaving}
+              >
+                <span>{t('kernel.versions.customMirrorConfirm')}</span>
+              </button>
+            </div>
+          </form>
+        </div>
+      ) : null}
+
       {/* Core Update Confirmation Dialog */}
       {confirmUpdateOpen ? (
         <div className="install-dialog-backdrop app-update-dialog-backdrop">

src/styles.css

@@ -1073,11 +1073,18 @@ textarea:focus-visible {
   color: var(--theme-9f2d20);
 }
 
-.version-source-control,
 .version-source-control label {
   display: grid;
 }
 
+.version-source-control {
+  display: grid;
+  grid-template-columns: minmax(0, 250px) auto;
+  width: max-content;
+  max-width: 100%;
+  gap: 8px;
+}
+
 .version-source-control select {
   width: 250px;
   max-width: 100%;
@@ -1100,6 +1107,29 @@ textarea:focus-visible {
   opacity: 0.58;
 }
 
+.version-source-add-button {
+  display: inline-flex;
+  min-height: 42px;
+  align-items: center;
+  justify-content: center;
+  gap: 6px;
+  padding: 0 12px;
+  border: 1px solid var(--theme-d5d2cb);
+  border-radius: 8px;
+  background: var(--theme-fffdf8);
+  color: var(--theme-4b4742);
+}
+
+.version-source-add-button:hover:not(:disabled) {
+  border-color: var(--theme-9b958c);
+  background: var(--theme-faf8f2);
+}
+
+.version-source-add-button:disabled {
+  cursor: not-allowed;
+  opacity: 0.58;
+}
+
 .version-card-grid {
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));
@@ -1674,6 +1704,15 @@ textarea:focus-visible {
   .version-source-control select {
     width: 100%;
   }
+
+  .version-source-control {
+    grid-template-columns: minmax(0, 1fr) auto;
+    width: 100%;
+  }
+
+  .version-source-add-button {
+    grid-column: 1 / -1;
+  }
 }
 
 .info-list {
@@ -8301,6 +8340,81 @@ body.table-col-resizing * {
   gap: 10px;
 }
 
+.custom-mirror-dialog {
+  width: min(500px, 100%);
+}
+
+.custom-mirror-dialog-description {
+  margin: 0;
+  color: var(--theme-6f6961);
+  font-size: var(--font-size-body);
+  line-height: var(--line-height-relaxed);
+}
+
+.custom-mirror-dialog > input {
+  width: 100%;
+  height: 44px;
+  min-width: 0;
+  padding: 0 12px;
+  border: 1px solid var(--theme-d5d2cb);
+  border-radius: 8px;
+  background: var(--theme-fffdf8);
+  color: var(--theme-2d2a26);
+}
+
+.custom-mirror-dialog-error {
+  color: var(--theme-9f2d20);
+  font-size: var(--font-size-meta);
+  line-height: var(--line-height-body);
+}
+
+.custom-mirror-dialog-list {
+  display: grid;
+  max-height: 150px;
+  gap: 6px;
+  overflow-y: auto;
+}
+
+.custom-mirror-dialog-list > span {
+  color: var(--theme-7a746c);
+  font-size: var(--font-size-meta);
+}
+
+.custom-mirror-dialog-list > div {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) 34px;
+  align-items: center;
+  gap: 8px;
+  padding: 6px 6px 6px 10px;
+  border: 1px solid var(--theme-e3e1db);
+  border-radius: 7px;
+  background: var(--theme-faf8f2);
+}
+
+.custom-mirror-dialog-list > div > span {
+  overflow: hidden;
+  color: var(--theme-4b4742);
+  font-size: var(--font-size-meta);
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.custom-mirror-dialog-list button {
+  display: grid;
+  width: 30px;
+  height: 30px;
+  place-items: center;
+  padding: 0;
+  border: 0;
+  border-radius: 6px;
+  background: transparent;
+  color: var(--theme-9f2d20);
+}
+
+.custom-mirror-dialog-list button:hover:not(:disabled) {
+  background: rgba(159, 45, 32, 0.08);
+}
+
 .app-update-dialog .install-dialog-message {
   display: flex;
   align-items: center;