✨ feat(update): 检查更新优先静态 latest.json，避免用户撞 GitHub API 限流

- 客户端优先下载 releases/latest/download/latest.json，再回退 REST API
- 成功结果写入磁盘缓存，限流/断网时可 stale 回退
- 静默检查增加节流；限流文案改为用户无需配置 Token
- CI 与 build-release 发版时生成 latest.json 清单
- 补充静态清单/缓存/节流单测与生成脚本测试

.github/workflows/release.yml

@@ -1081,6 +1081,24 @@ jobs:
             sha256sum "${FILES[@]}" > SHA256SUMS
           fi
 
+      # 静态更新清单：客户端优先下载 github.com/.../latest/download/latest.json，
+      # 避免终端用户检查更新打爆 api.github.com 未认证配额。
+      - name: Generate static update manifest (latest.json)
+        shell: bash
+        run: |
+          set -euo pipefail
+          TAG="${{ github.ref_name }}"
+          VERSION="${TAG#v}"
+          python3 tools/generate-update-latest-manifest.py \
+            --assets-dir release-assets \
+            --version "$VERSION" \
+            --tag "$TAG" \
+            --channel latest \
+            --output release-assets/latest.json
+          test -s release-assets/latest.json
+          echo "📄 latest.json ready:"
+          head -n 40 release-assets/latest.json
+
       - name: Generate Driver SHA256SUMS
         if: steps.driver_assets.outputs.has_driver_assets == 'true'
         shell: bash