fix: prevent dashboard hydration crash from undefined usageStats fields

src/stores/auth-store.ts

@@ -13,6 +13,31 @@ interface UsageStats {
   };
 }
 
+// Normalize usage stats at the boundary (API responses + localStorage rehydration).
+// Guarantees the full shape so render code can trust .toLocaleString() on every field.
+// Without this, a stale persisted shape or a partial API response crashes the dashboard
+// during hydration with "Cannot read properties of undefined (reading 'toLocaleString')".
+function normalizeUsageStats(stats: unknown): UsageStats | null {
+  if (!stats || typeof stats !== "object") return null;
+  const s = stats as Partial<UsageStats> & {
+    limits?: Partial<UsageStats["limits"]>;
+    usage?: Partial<UsageStats["usage"]>;
+  };
+  const num = (v: unknown, fallback = 0): number =>
+    typeof v === "number" && Number.isFinite(v) ? v : fallback;
+  return {
+    planName: typeof s.planName === "string" && s.planName.length > 0 ? s.planName : "Free",
+    limits: {
+      uploads: num(s.limits?.uploads),
+      profiles: num(s.limits?.profiles),
+    },
+    usage: {
+      uploads: num(s.usage?.uploads),
+      profiles: num(s.usage?.profiles),
+    },
+  };
+}
+
 interface AuthState {
   apiKey: string | null;
   usageStats: UsageStats | null;
@@ -36,7 +61,7 @@ export const useAuthStore = create<AuthState>()(
       error: null,
       hasHydrated: false,
       setApiKey: (key) => set({ apiKey: key, error: null }),
-      setUsageStats: (stats) => set({ usageStats: stats }),
+      setUsageStats: (stats) => set({ usageStats: normalizeUsageStats(stats) }),
       setIsValidating: (validating) => set({ isValidating: validating }),
       setError: (error) => set({ error }),
       setHasHydrated: (hydrated) => set({ hasHydrated: hydrated }),
@@ -53,8 +78,14 @@ export const useAuthStore = create<AuthState>()(
         apiKey: state.apiKey,
         usageStats: state.usageStats,
       }),
+      // Sanitize the rehydrated shape before the dashboard mounts. Old persisted
+      // shapes (pre-normalize) or any localStorage corruption get coerced to a
+      // safe default instead of crashing the layout on first paint.
       onRehydrateStorage: () => (state) => {
-        state?.setHasHydrated(true);
+        if (state) {
+          state.usageStats = normalizeUsageStats(state.usageStats);
+          state.setHasHydrated(true);
+        }
       },
     }
   )