feat(followup): implement PLAN-FOLLOWUP.md gap fixes

Complete implementation of 7 slices addressing E2E testing gaps:

Slice 0+1: Wire Actions + ReasonPrompt
- FocusView now uses useActions hook instead of direct act() calls
- Added pendingAction state pattern for skip/defer/complete actions
- ReasonPrompt integration with proper confirm/cancel flow
- Tags support in DecisionEntry interface

Slice 2: Drag Reorder UI
- Installed @dnd-kit (core, sortable, utilities)
- QueueView with DndContext, SortableContext, verticalListSortingStrategy
- SortableQueueItem wrapper component using useSortable hook
- pendingReorder state with ReasonPrompt for reorder reasons
- Cmd+Up/Down keyboard shortcuts for accessibility
- Fixed: Store item ID in PendingReorder to avoid stale queue reference

Slice 3: System Tray Integration
- tray.rs with TrayState, setup_tray, toggle_window_visibility
- Menu with Show/Quit items
- Left-click toggles window visibility
- update_tray_badge command updates tooltip with item count
- Frontend wiring in AppShell

Slice 4: E2E Test Updates
- Fixed test selectors for InboxView, Queue badge
- Exposed inbox store for test seeding

Slice 5: Staleness Visualization
- Already implemented in computeStaleness() with tests

Slice 6: Quick Wiring
- onStartBatch callback wired to QueueView
- SyncStatus rendered in nav area
- SettingsView renders Settings component

Slice 7: State Persistence
- settings-store with hydrate/update methods
- Tauri backend integration via read_settings/write_settings
- AppShell hydrates settings on mount

Bug fixes from code review:
- close_bead now has error isolation (try/catch) so decision logging
  and queue advancement continue even if bead close fails
- PendingReorder stores item ID to avoid stale queue reference

E2E tests for all ACs (tests/e2e/followup-acs.spec.ts):
- AC-F1: Drag reorder (4 tests)
- AC-F2: ReasonPrompt integration (7 tests)
- AC-F5: Staleness visualization (3 tests)
- AC-F6: Batch mode (2 tests)
- AC-F7: SyncStatus (2 tests)
- ReasonPrompt behavior (3 tests)

Tests: 388 frontend + 119 Rust + 32 E2E all passing

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/mocks/tauri-api.ts

@@ -39,10 +39,19 @@ export const invoke = vi.fn(async (cmd: string, _args?: unknown) => {
       return { created: 0, closed: 0, skipped: 0, healed: 0, errors: [] };
     case "quick_capture":
       return { bead_id: "bd-mock-capture" };
+    case "get_triage":
+      return {
+        generated_at: new Date().toISOString(),
+        counts: { open: 5, actionable: 3, blocked: 1, in_progress: 1 },
+        top_picks: [],
+        quick_wins: [],
+        blockers_to_clear: [],
+      };
     case "read_state":
       return null;
     case "write_state":
     case "clear_state":
+    case "update_tray_badge":
       return null;
     default:
       throw new Error(`Mock not implemented for command: ${cmd}`);