Replace RenderNotifier with clean AppState and RenderCache singletons:
- Add AppState.shared static singleton for global access
- Add RenderCache.shared static singleton for memoization
- Remove RenderNotifier enum completely
- Remove RenderNotifierKey from EnvironmentValues
- StateBox.didSet uses AppState.shared directly
- AppStorage.wrappedValue setter uses AppState.shared directly
- NotificationService.post() uses AppState.shared directly
- Spinner animation uses AppState.shared directly
- NotificationHostModifier animation uses AppState.shared directly
- TUIContext uses RenderCache.shared by default (injectable for tests)
- Update test infrastructure to isolate RenderCache per test
Architecture: Pure singleton pattern with no global state registry.
All 1069 tests pass, no new compiler warnings.
This completes the full elimination of RenderNotifier and provides a
clean, explicit architecture where AppState.shared is the single
source of truth for render triggers.
- Make RenderNotifier.current optional (nil by default) to support DI
- Add RenderNotifierKey and renderNotifier property to EnvironmentValues
- Initialize renderNotifier in RenderLoop.buildEnvironment()
- Migrate Spinner animation loop to read from environment
- Migrate NotificationHostModifier to read from environment via parameter
- Update StateBox.didSet to use optional chaining fallback
- Update AppStorage.wrappedValue setter to use optional chaining fallback
- Update NotificationService.post() to use optional chaining fallback
- Update test comments to reflect optional chaining pattern
- All 1069 tests pass, no new compiler warnings
Phase 3 implementation of P4.16 dependency injection refactor complete.
- Add comprehensive documentation to RenderNotifier static properties
explaining main-thread-only access guarantees and safety model
- Add inline safety comments to Terminal memory operations
explaining why unsafe memory rebinding is safe in context
Audit findings: All concurrency patterns are justified, documented,
and safe. No critical issues found. These are quality-of-life improvements
for code maintainability.
phranck