Improve horizontal layout scroll performance by removing React sync flushing

[radubrehar]

Note

Medium Risk
Changes the cell render/positioning timing during horizontal scrolling by moving work to a post-commit hook, which could introduce subtle visual/interaction regressions (mispositioned cells, hover/z-index timing) despite being performance-motivated.

Overview
Improves horizontal layout scrolling performance by removing the previous flushSync-based update path in AvoidReactDiff and replacing it with an afterCommit hook.

GridCellInterface/cell implementations now support setPendingAfterCommitWork, and ReactHeadlessTableRenderer.updateElementPosition defers applying transforms/styles until after React commits only while horizontal scrolling.

Updates perf CI baselines accordingly and adds/adjusts horizontal layout example pages to exercise the new behavior.

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