perf: P0 performance optimizations — memo, base64 cleanup, startup speed, bump v0.17.5
Six independent fixes targeting startup lag, streaming jank, and excessive payloads:
Step 0 — MessageItem React.memo + useMemo (MessageItem.tsx)
- Wrap MessageItem with React.memo so historical messages skip re-render
when `message` ref is stable during streaming
- Add useMemo for parseToolBlocks + pairTools (deps: message.content),
parseMessageFiles (deps: text), token_usage JSON.parse (deps: message.token_usage)
- Extract assistant content rendering into separate memo'd AssistantContent component
to cache parseBatchPlan / parseImageGen chain (deps: displayText, messageId)
- Root cause: 50 msgs × 10 SSE events/s = 500 full parses/s causing UI jank
Step 1 — Strip base64 from new messages (ChatView.tsx, route.ts)
- ChatView: remove `data: f.data` from fileMeta in display content HTML comment
- route.ts: skip base64 data in fileAttachments when filePath exists (file already on disk)
- Root cause: base64 image data inflated message content to MB-level
Step 2 — Sanitize old messages in API (messages/route.ts)
- Add stripFileData() to strip base64 `data` fields from <!--files:...--> comments
before returning messages from GET /api/chat/sessions/:id/messages
- Handles legacy data already stored with base64
Step 3 — Reduce initial fetch limit 100 → 30 (page.tsx, messages/route.ts)
- Default limit changed from 100 to 30 on both frontend and backend
- "Load more" functionality unchanged
Step 4 — ChatListPanel dedup requests (ChatListPanel.tsx)
- Remove duplicate pathname-dependent useEffect (was causing 2 fetches per navigation)
- Add AbortController to cancel in-flight requests on new fetch
- Add 300ms debounce for event-driven fetches (session-created/session-updated)
Step 5 — Electron startup: show window before server ready (electron/main.ts)
- createWindow() now accepts optional URL, defaults to inline loading HTML
- Loading page: dark theme, centered spinner, "Starting CodePilot..." text
- Startup: startServer() → createWindow(loading) → waitForServer() → loadURL(real)
- Also updated activate handler for same early-window pattern
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
