* fix: restore git changes panel visibility and sidebar sync
Two independent fixes:
1. ChangesSection virtualizer returned empty rows due to useMemo caching
getVirtualItems() with a stale stable reference. First render produced
an empty array, and useMemo never recomputed because rowVirtualizer
reference never changed. Removed the useMemo to call getVirtualItems()
directly on every render. Also added a ResizeObserver to force
remeasurement on visibility transitions (defensive).
2. RightSidebarTabs now keeps git status fresh while the sidebar is open
via useRightSidebarGitSync hook (10s polling with ensureStatus).
Replaces the GitPollingProvider removed in commit d9821716.
* fix(virtualizer): prevent React error #185 from render-phase getVirtualItems
Restoring useMemo for virtualRows with totalSize as an invalidation
dependency. Calling getVirtualItems() directly during render triggers
the virtualizer's maybeNotify() → onChange() → useReducer dispatch,
causing React error #185 (https://react.dev/errors/185 — cannot
update a component while rendering a different component).
The original useMemo([rowVirtualizer, shouldVirtualize]) was removed
because rowVirtualizer is a stable useState ref that never changes,
leaving the memo permanently stale after the first empty render.
Adding totalSize (from getTotalSize()) as a dependency solves this:
it changes whenever the virtualizer recalculates after measure/scroll,
ensuring getVirtualItems() returns fresh rows while staying wrapped
in useMemo.
jwcrystal
700138c9b5