feat(tui): add usage overlay and sidebar for displaying usage statistics and tasks

feat(tui): implement status bar with connection and turn state indicators
feat(tui): create workflow panel for agent status and progress visualization
feat(web): introduce web frontend interface with static file serving
feat(ws): add WebSocket interface for real-time communication and session management

apps/interfaces/api/src/dto/mod.rs

@@ -0,0 +1,10 @@
+//! Data Transfer Objects for the REST API.
+//!
+//! These types define the wire format for request bodies and response bodies.
+//! They are intentionally independent of domain entities so the API contract
+//! can evolve without coupling to the domain model.
+
+pub mod auth;
+pub mod conversation;
+pub mod error;
+pub mod session;