🤖 fix: coalesce ResizeObserver scrolls to prevent 1px visual flakiness #1264
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The useAutoScroll hook's ResizeObserver was setting scrollTop synchronously on every resize event. During async content rendering (Shiki highlighting, Mermaid diagrams, images), this caused multiple scrolls per frame with slightly different scrollHeight values, leading to 1px scroll offset flakiness in visual regression tests. Changes: - Add RAF coalescing to ResizeObserver callback in useAutoScroll - Simplify story helpers to use a single RAF wait after message load - Remove complex multi-frame scroll stabilization from stories
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The useAutoScroll hook's ResizeObserver callback was using an
if (rafIdRef.current !== null) returnguard for coalescing, but the stories were still seeing 1px scroll offsets during visual regression tests.Changes
??=operator for cleaner RAF coalescing in ResizeObserver callbackThe production code now properly coalesces all resize events within a frame into a single scroll operation, making scroll positions deterministic for visual regression testing.
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