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/hash.ts

@@ -0,0 +1,12 @@
+/**
+ * FNV-1a 32-bit hash — same hash the gateway uses to tag PCM frames.
+ * Shared between use-voice hooks and ambient-canvas.
+ */
+export function hashUserId(userId: string): number {
+  let hash = 0x811c9dc5;
+  for (let i = 0; i < userId.length; i++) {
+    hash ^= userId.charCodeAt(i);
+    hash = Math.imul(hash, 0x01000193);
+  }
+  return hash >>> 0;
+}

services/frontend/src/lib/swr-config.ts

@@ -0,0 +1,47 @@
+/**
+ * Global SWR configuration for the GMW frontend.
+ *
+ * Centralizes revalidation policy, error retry with exponential backoff, and
+ * deduplication so every `useSWR` call across the app gets consistent behaviour
+ * without each hook re-declaring the same options.
+ *
+ * Import this in the root layout (or any component mounted once) via
+ * `SWRConfig` from "swr".
+ */
+
+import type { SWRConfiguration } from "swr";
+
+/**
+ * Exponential backoff retry — starts at ~1s, doubles up to 30s, then flatlines.
+ * Matches the existing WsConnection reconnection philosophy.
+ */
+export const swrConfig: SWRConfiguration = {
+  // Re-validate on focus (tab switch) but not on every interval by default.
+  revalidateOnFocus: true,
+  // Dedupe rapid identical requests within 2s.
+  dedupingInterval: 2000,
+  // Never throw unhandled rejections — every hook handles `error` gracefully.
+  shouldRetryOnError: (error) => {
+    // Don't retry on 404 (NotFound) — it's a client expectation, not transient.
+    if (error?.statusCode === 404 || error?.code === "NOT_FOUND") return false;
+    // Retry network errors, 5xx, and oRPC transport failures.
+    return true;
+  },
+  onErrorRetry: (_error, _key, _config, revalidate, opts) => {
+    const attemptCount = (opts as { attemptCount?: number }).attemptCount ?? 0;
+    // Stop retrying after 3 attempts (≈ 1+2+4 = 7s max backoff).
+    if (attemptCount >= 3) return;
+
+    // Exponential backoff: 1000 * 2^attempt, capped at 30000ms.
+    const baseDelay = 1000 * 2 ** attemptCount;
+    const delay = Math.min(baseDelay, 30000);
+
+    // Jitter ±25% to avoid thundering herd on shared endpoints.
+    const jitter = delay * 0.25 * (Math.random() * 2 - 1);
+    const timeout = Math.round(delay + jitter);
+
+    setTimeout(revalidate, timeout);
+  },
+  // Sensible defaults for the "loading" state — most data loads in <500ms.
+  loadingTimeout: 15000,
+};

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 () => {

services/frontend/src/lib/ws/context.tsx

@@ -9,6 +9,7 @@ import {
   useRef,
   useState,
 } from "react";
+import { toast } from "@/components/primitives";
 import { WsConnection } from "./connection";
 import type { PcmChunk, WsEventHandler, WsEventType, WsStatus } from "./types";
 
@@ -29,16 +30,6 @@ interface WsContextValue {
 
 const WsContext = createContext<WsContextValue | null>(null);
 
-/** FNV-1a 32-bit hash matching the backend's hashUserId function */
-function _hashUserId(userId: string): number {
-  let hash = 0x811c9dc5;
-  for (let i = 0; i < userId.length; i++) {
-    hash ^= userId.charCodeAt(i);
-    hash = Math.imul(hash, 0x01000193);
-  }
-  return hash >>> 0;
-}
-
 export function WsProvider({
   children,
   url,
@@ -48,6 +39,9 @@ export function WsProvider({
 }) {
   const connRef = useRef<WsConnection | null>(null);
   const [status, setStatus] = useState<WsStatus>("disconnected");
+  // Tracks whether we've ever been connected — used to suppress the
+  // "reconnecting" toast on initial page load.
+  const wasConnected = useRef(false);
 
   // Event handler registry — Ref so listeners survive re-renders without reconnect
   // Using unknown as internal store; typed at the subscribe interface
@@ -85,7 +79,31 @@ export function WsProvider({
     const conn = new WsConnection(url);
     connRef.current = conn;
 
-    const unsubStatus = conn.onStatusChange(setStatus);
+    const unsubStatus = conn.onStatusChange((s) => {
+      setStatus(s);
+      // User feedback on WS lifecycle transitions.
+      if (s === "connecting") {
+        // Only toast if we were previously connected (i.e. a disconnect,
+        // not the initial connect on page load).
+        if (wasConnected.current) {
+          toast({
+            title: "Reconnecting…",
+            description: "WebSocket connection lost. Attempting to reconnect.",
+            tone: "neutral",
+          });
+        }
+        wasConnected.current = false;
+      } else if (s === "connected") {
+        wasConnected.current = true;
+      } else if (s === "error" && !wasConnected.current) {
+        toast({
+          title: "Connection error",
+          description:
+            "WebSocket failed to connect. Retrying in the background.",
+          tone: "vermilion",
+        });
+      }
+    });
     const unsubEvent = conn.onEvent((event) => {
       if (event.type === "text") {
         handleJsonEvent(event.data);