feat: multi-tenant auth with per-user scoping

Multi-user authentication and authorization for IronClaw gateway:
- Token-based auth mapping tokens to user IDs via GATEWAY_USER_TOKENS
- Per-user SSE broadcast scoping
- Per-user rate limiting with poisoned lock recovery
- Handler auth and ownership checks for jobs, settings, routines
- Extension secrets scoped per-user
- Chat handlers use authenticated identity
- Reverse proxy deployment documentation
- Comprehensive integration tests for auth, SSE, rate limiting, and job isolation

tests/module_init_integration.rs

@@ -216,7 +216,7 @@ async fn extension_manager_with_process_manager_constructs() {
     );
 
     // Verify the manager is functional — list returns Ok.
-    let result = manager.list(None, false).await;
+    let result = manager.list(None, false, "test").await;
     assert!(result.is_ok(), "list should succeed on empty manager");
     assert!(result.unwrap().is_empty());
 }