chat-perflisted

# Chat Performance Testing ## When to use - Before/after modifying chat rendering code (`chatListRenderer.ts`, `chatInputPart.ts`, markdown rendering) - When changing the streaming response pipeline or SSE processing - When modifying disposable/lifecycle patterns in chat components - To compare performance between two VS Code releases - In CI to gate PRs that touch chat UI code ## Quick start ```bash # Run perf regression test (compares local dev build vs VS Code 1.115.0): npm run perf:chat -- --scenario text-only --runs 3 # Run all scenarios with no baseline (just measure): npm run perf:chat -- --no-baseline --runs 3 # Compare two local builds (apples-to-apples): npm run perf:chat -- --build /path/to/build-A --baseline-build /path/to/build-B --runs 5 # Build a local production package and compare against a release: npm run perf:chat -- --production-build --baseline-build 1.115.0 --runs 5 # Run memory leak check (10 messages in one session): npm run perf:chat-leak # Run leak check with more messages for accuracy: npm run perf:chat-leak -- --messages 20 --verbose ``` ## Perf regression test **Script:** `scripts/chat-simulation/test-chat-perf-regression.js` **npm:** `npm run perf:chat` Launches VS Code via Playwright Electron, opens the chat panel, sends a message with a mock LLM response, and measures timing, layout, and rendering metrics. By default, downloads VS Code 1.115.0 as a baseline, benchmarks it, then benchmarks the local dev build and compares. ### Key