feat: dynamic SIP from agentConfig, logout cleanup, heartbeat

- SIP provider reads credentials from agentConfig (login response)
- Auth logout calls sidecar to unlock Redis + Ozonetel logout
- AppShell heartbeat every 5 min for CC agents
- Login stores agentConfig in localStorage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/providers/auth-provider.tsx

@@ -96,10 +96,21 @@ export const AuthProvider = ({ children }: AuthProviderProps) => {
     }, []);
 
     const logout = useCallback(() => {
+        // Notify sidecar to unlock Redis session + Ozonetel logout
+        const token = localStorage.getItem('helix_access_token');
+        if (token) {
+            const apiUrl = import.meta.env.VITE_API_URL ?? 'http://localhost:4100';
+            fetch(`${apiUrl}/auth/logout`, {
+                method: 'POST',
+                headers: { Authorization: `Bearer ${token}` },
+            }).catch(() => {});
+        }
+
         setUser(DEFAULT_USER);
         setIsAuthenticated(false);
         localStorage.removeItem('helix_access_token');
         localStorage.removeItem('helix_refresh_token');
+        localStorage.removeItem('helix_agent_config');
         localStorage.removeItem(STORAGE_KEY);
     }, []);