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/components/DebugView.test.tsx

@@ -108,7 +108,7 @@ describe("DebugView", () => {
     expect(screen.getByTestId("health-indicator")).toHaveClass("bg-red-500");
   });
 
-  it("displays last sync time when available", async () => {
+  it("displays 'data since' timestamp when available", async () => {
     const mockStatus = {
       last_sync: "2026-02-26T12:00:00Z",
       is_healthy: true,
@@ -128,7 +128,7 @@ describe("DebugView", () => {
     expect(syncTimeElements.length).toBeGreaterThan(0);
   });
 
-  it("shows 'never' when last_sync is null", async () => {
+  it("shows 'all time' when last_sync is null", async () => {
     const mockStatus = {
       last_sync: null,
       is_healthy: false,
@@ -143,6 +143,6 @@ describe("DebugView", () => {
       expect(screen.queryByText(/loading/i)).not.toBeInTheDocument();
     });
 
-    expect(screen.getByText(/never/i)).toBeInTheDocument();
+    expect(screen.getByText(/all time/i)).toBeInTheDocument();
   });
 });