Two audit findings on the ambient-animation gate:

- The one-shot `isReduceMotionEnabled()` read could resolve after a
  `reduceMotionChanged` event and overwrite the newer value. Signal folding
  now treats the initial read as "only lands while unreported" and lets
  events always win; ordering is covered by focused tests.
- Each `ConnectionStatusDot` installed its own AppState and AccessibilityInfo
  listeners. Platform signals move to a module-level store behind
  `useSyncExternalStore`: one shared pair of native subscriptions for all
  consumers, bounded for the app lifetime.