Phase 8: player view (local/projector) + sync seam

- Player View (/play): read-only projector screen — party HP bars + conditions,
  active-encounter initiative with current turn; enemy HP hidden behind a
  Healthy/Bloodied/Down status band; Fullscreen button
- SyncAdapter seam (src/lib/sync): local-first default via Dexie liveQuery;
  documents where a future networked (WebSocket/CRDT) backend plugs in
- Dashboard + routes get a Player View entry
- Robustness: encountersRepo.mutate() does transactional read-modify-write so
  rapid combat mutations can't overwrite each other (old C19 race); tracker uses it

New player-view e2e. Networked multiplayer backend intentionally deferred.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/features/world/DashboardPage.tsx

@@ -22,6 +22,7 @@ const LINKS = [
   { to: '/calendar', label: 'Calendar', icon: '📅' },
   { to: '/compendium', label: 'Compendium', icon: '📚' },
   { to: '/dice', label: 'Dice', icon: '🎲' },
+  { to: '/play', label: 'Player View', icon: '📺' },
 ] as const;
 
 function Dashboard({ campaign }: { campaign: Campaign }) {