fix(release): enable signed Electron release updates

Tested: bun test scripts/pr/release-workflow.test.ts scripts/release-update-metadata.test.ts scripts/quality-gate/package-smoke/index.test.ts
Tested: bun run check:policy
Tested: bun run check:docs
Tested: workflow YAML parse and git diff --check
Scope-risk: moderate

docs/.vitepress/config.mts

@@ -95,6 +95,7 @@ const zhSidebar = [
       { text: 'Electron 迁移调研', link: '/desktop/07-electron-migration-research' },
       { text: 'Electron 迁移任务', link: '/desktop/08-electron-migration-tasks' },
       { text: 'Electron 迁移验证', link: '/desktop/09-electron-migration-validation-checklist' },
+      { text: 'Electron 发布与更新', link: '/desktop/10-release-auto-update' },
     ],
   },
   {