feat(fe): optimize error handling, state consistency, and WS feedback

- Add global SWR config with exponential backoff retry (swr-config.ts)
- Add ErrorBoundary component for React crash recovery (error-boundary.tsx)
- Standardize ErrorState onRetry on all 6 dashboard views (dashboard, media,
  messages, moderation, recordings, voice)
- Fix useAction: expose resetError + onError callback
- Refactor useSpeakers to SWR-backed state (was local useState) for
  consistent cache/revalidate semantics with other hooks
- Remove polling in useReview (15s refreshInterval); replace with
  useReviewWsSync subscribing to WS moderation_action events
- Extract hashUserId to lib/hash.ts (de-dup with ambient-canvas)
- WS context: add reconnect/error toast feedback via onStatusChange
- WS connection: expose reconnectAttemptCount getter

All typecheck + lint clean, Next 16 build passes.

services/frontend/src/lib/ws/connection.ts

@@ -37,6 +37,11 @@ export class WsConnection {
     return this._status;
   }
 
+  /** Current reconnect attempt count (0 = connected/first attempt). */
+  get reconnectAttemptCount(): number {
+    return this.reconnectAttempt;
+  }
+
   onStatusChange(listener: (status: WsStatus) => void): () => void {
     this.statusListeners.push(listener);
     return () => {