refactor: remove local bin/ fallback, download only from GitHub Release

- Remove Strategy 2 (fallback to local bin/) from installer.ts
- Binary source is now exclusively GitHub Release (preset tag)
- Improve error message with direct download link on failure
- Update CHANGELOG.md to reflect the change
- Developers can self-build via codeagent-wrapper/build-all.sh

CHANGELOG.md

@@ -13,7 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **二进制产物迁移至 GitHub Release**：`bin/codeagent-wrapper-*` 不再打包到 npm 和 git，改从 GitHub Release (`preset` tag) 按需下载，npm 包从 16.3MB 缩减至 161KB
 - **GitHub Actions CI**：新增 `.github/workflows/build-binaries.yml`，`codeagent-wrapper/` 变更时自动交叉编译 6 平台并上传到 `preset` Release
-- **installer.ts 下载逻辑**：优先从 GitHub Release 下载，失败后 fallback 到本地 `bin/`（开发/离线场景）
+- **installer.ts 下载逻辑**：仅从 GitHub Release 下载，移除本地 `bin/` fallback（开发者可用 `build-all.sh` 自行编译）
+- **移除本地二进制**：`bin/codeagent-wrapper-*` 6 个文件已从仓库删除，仅保留 `bin/ccg.mjs` 入口
 
 ---
 

src/utils/installer.ts

@@ -845,26 +845,8 @@ ${workflow.description}
 
     const destBinary = join(binDir, platform === 'win32' ? 'codeagent-wrapper.exe' : 'codeagent-wrapper')
 
-    // Strategy 1: Download from GitHub Release (preferred)
-    let installed = false
-    try {
-      installed = await downloadBinaryFromRelease(binaryName, destBinary)
-    }
-    catch {
-      // Download failed, will try fallback
-    }
-
-    // Strategy 2: Fallback to local bin/ (development or offline)
-    if (!installed) {
-      const srcBinary = join(PACKAGE_ROOT, 'bin', binaryName)
-      if (await fs.pathExists(srcBinary)) {
-        await fs.copy(srcBinary, destBinary)
-        if (platform !== 'win32') {
-          await fs.chmod(destBinary, 0o755)
-        }
-        installed = true
-      }
-    }
+    // Download from GitHub Release (only source)
+    const installed = await downloadBinaryFromRelease(binaryName, destBinary)
 
     if (installed) {
       // Verify installation by running --version
@@ -880,7 +862,7 @@ ${workflow.description}
       }
     }
     else {
-      result.errors.push(`Failed to obtain binary: ${binaryName} (download failed, no local fallback)`)
+      result.errors.push(`Failed to download binary: ${binaryName} from GitHub Release. Check network or visit https://github.com/${GITHUB_REPO}/releases/tag/${RELEASE_TAG}`)
       result.success = false
     }
   }