feat(02-05): letter overlay + settings UI + boot save lifecycle + clock injection

- src/save/payload.ts (W2): shared buildPayloadFromStore (state, nowMs)
  + hydrateStoreFromPayload (state, payload). Two-arg signature unifies
  Settings.tsx (passes Date.now()) and PhaserGame.tsx saveSync (passes
  clock.now()). BLOCKER 3 — lastTickAt is wall-clock ms, owned by the
  application layer; the sim never writes it.
- src/ui/letter/Letter.tsx + test: D-20 full-screen overlay (UX-02);
  loads compiled letter Ink, binds plants_bloomed/fragment_titles/
  lura_was_here slots from session.pendingLetterEventBlock, dismisses
  via Tend the garden button or backdrop click. Pitfall 9 — dismiss
  calls bootstrapAudioContext synchronously inside the click handler.
- src/ui/settings/Settings.tsx + test: D-28 save-management UI
  (Export/Import/Restore). BLOCKER 2 — Import pipeline is
  importFromBase64 -> unwrap (CRC verify) -> migrate -> hydrate. No
  audio sliders, no a11y polish (Phase 8 owns those).
- src/ui/settings/persistence-toast.tsx: D-30 one-time soft toast in
  voice when navigator.storage.persist() denies. Reads
  showPersistenceToast from session slice; sets persistenceToastShown
  after the timeout fires.
- src/PhaserGame.tsx: full boot path rewrite. Clock selection
  (?devtime=fake URL flag, production-guarded by import.meta.env.PROD),
  save load (BLOCKER 1 — unwrap then migrate), silent offline catchup
  via drainTicks(silent=true), letter overlay open at >=5min absence,
  requestPersistence + showPersistenceToast wiring, Phaser start AFTER
  hydration, registerSaveLifecycleHooks with synchronous LocalStorage
  saveSync (Pitfall 7) + best-effort IDB write. W5 — lifecycle handle
  held in ref so outer cleanup detaches.
- src/store/session-slice.ts: showPersistenceToast transient flag +
  setShowPersistenceToast action.
- src/ui/journal/journal-icon.tsx: 'j' hotkey listener via
  tlg:toggle-journal CustomEvent (D-29).
- src/game/scenes/Garden.ts: formalized clock read via readClockSlot()
  helper; falls back to wallClock if window.__tlgClock missing.
- src/App.tsx: mount Letter, Settings, PersistenceToast, SettingsIcon
  (corner button); D-29 keyboard shortcuts (',' toggles Settings, 'j'
  toggles Journal via window event).
- 308/308 tests green (was 295; +13 new — 7 Letter + 6 Settings).
  npm run ci exits 0; Vite emits letter Ink as a separate lazy chunk.

src/ui/journal/journal-icon.tsx

@@ -31,6 +31,17 @@ export function JournalIcon(): JSX.Element | null {
     if (!revealed && open) setOpen(false);
   }, [revealed, open]);
 
+  // Plan 02-05 — D-29 'j' hotkey listens for the App-dispatched
+  // CustomEvent to toggle the journal modal. Keeping the open/close
+  // state local here (rather than lifting into the store) preserves
+  // V1Payload's no-journal-open-flag invariant.
+  useEffect(() => {
+    if (!revealed) return;
+    const onToggle = (): void => setOpen((v) => !v);
+    window.addEventListener('tlg:toggle-journal', onToggle);
+    return () => window.removeEventListener('tlg:toggle-journal', onToggle);
+  }, [revealed]);
+
   if (!revealed) return null;
 
   return (