Renderer responsiveness run manifest

• Mode: publish
• Milestone: user-visible lag audit and renderer update coalescing
• Expected UI state: the application shell paints immediately on a disposable repository and remains responsive while repeated app-state updates arrive.
• Ordered background interactions:
  1. build current main without packaging through Lowlevel MCP;
  2. create one isolated Win32 headless desktop;
  3. launch the built Electron app with isolated user data and a disposable Git fixture;
  4. capture startup timing, renderer long tasks, and repeated-update behavior;
  5. exercise repository navigation using HWND-targeted background input;
  6. capture and inspect the final client image;
  7. close the exact window/PID and remove only owned temporary paths.
• Disposable fixture path: %TEMP%\desktop-material-renderer-perf-20260728
• Screenshot target: %TEMP%\desktop-material-renderer-perf-20260728\final.png
• Theme and dimensions: default theme, 1180×820
• Documentation allowlist: this verification directory, quality/reliability feature documentation, README.md, ROADMAP.md, and HANDOFF.md
• Tests: focused update-coalescing tests, related lifecycle tests, ESLint, TypeScript, production build, headless launch and interaction
• Remote: origin
• Expected branch: main
• Initial baseline: clean main at 9bdfdb8b25e458e4834bdaa26473d44a5602621d; the separate codex/close-all-open-issues-20260728 worktree is dirty and must remain untouched.