feat(bd-3rf): Add comprehensive TUI regression test suite

- Created comprehensive regression test suite with 73 new tests
- Test coverage includes:
  - Component integration and coordination
  - View mode transitions (heatmap, DAG, replay, errors, etc.)
  - Focus mode behavior with worker/bead pinning
  - Keyboard navigation and bindings
  - Command palette integration
  - Error handling and edge cases
  - Performance and resource management
  - State consistency across renders
  - Rendered output format validation

All 1213 tests pass (3 skipped), verifying no regressions in TUI functionality.

Co-Authored-By: Claude Worker <noreply@anthropic.com>

src/tui/regression.test.ts

@@ -966,9 +966,9 @@ describe('TUI Regression Tests', () => {
       app = new FabricTuiApp(store);
       app.start();
 
-      // Add events
+      // Add events to store
       for (let i = 0; i < 10; i++) {
-        app.addEvent(createMockEvent({ msg: `Event ${i}` }));
+        store.add(createMockEvent({ msg: `Event ${i}` }));
       }
 
       // Switch views