Optimize chat timeline render stability

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What Changed

• Removed React Compiler blockers in MessagesTimeline by replacing render-time ref cache mutation with guarded render-state structural sharing.
• Replaced dynamic Lucide icon component rendering in work-log rows with static top-level icon components.

Why

react-doctor flagged MessagesTimeline.tsx for performance errors (refs and static-components) that prevented React Compiler optimization on a hot streaming chat path. The new implementation preserves unchanged row references while avoiding ref reads/writes during render, and makes work-log icon rendering compiler-friendly.

UI Changes

No intentional visual UI change. React Scan recordings captured the same timeline pulse interaction before and after:

• Before: react_scan_timeline_before.mp4
• After: react_scan_timeline_after.mp4

Video review confirmed the before recording highlighted larger timeline/message wrappers, while the after recording localized highlights to the changing streaming text/timer.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Validation:

• react-doctor ./apps/web --json --no-score --blocking none (MessagesTimeline.tsx: 3 errors before, 0 errors after)
• vp check
• vp run typecheck
• vp test run --passWithNoTests --project unit src/components/chat/MessagesTimeline.test.tsx

  

Note

Optimize chat timeline render stability in MessagesTimeline

• Refactors useStableRows to cache a StableRowsSnapshot in React state and update it when the input rows reference changes, replacing the previous useMemo/ref approach for more reliable structural sharing.
• Extracts createStableRowsSnapshot as a standalone helper to package stable row computation for reuse.
• Splits icon rendering into two new components, WorkToneIconGlyph and WorkEntryIconGlyph, which return rendered JSX instead of icon types; workToneIconClass now returns only a CSS class string.

^{Macroscope summarized 53eea2a.}

[github-actions]

🚀 Expo continuous deployment is ready!

• Project → t3-code
• Platforms → android, ios
• Scheme → t3code-preview

	🤖 Android	🍎 iOS
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