* fix(app): eliminate terminal scroll lag by removing MutationObserver and throttling scroll events
The MutationObserver with subtree:true was firing React setState on every
xterm DOM mutation (character output, cursor blink, scroll line rendering),
causing cascading React re-renders that blocked the main thread and made
the mouse wheel unresponsive on web.
Changes:
- Remove MutationObserver (redundant with ResizeObserver for viewport sizing)
- Throttle scroll handler with requestAnimationFrame to batch setState calls
- Early-return in updateViewportMetrics when metrics unchanged since last emit
- Cancel pending rAF on cleanup to avoid stale updates
Co-Authored-By: TommyLike <tommylikehu@gmail.com>
* Fix terminal scrollbar metric dedupe state
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Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>
