feat: add object storage REST API

File-based object storage with GET/PUT/DELETE, directory listing,
path traversal protection, and streaming upload up to 2GB.

src/api/mod.rs

@@ -1,5 +1,7 @@
 mod kb;
+pub mod obj;
 mod projects;
+mod settings;
 mod timers;
 mod workflows;
 
@@ -28,6 +30,7 @@ pub fn router(state: Arc<AppState>) -> Router {
         .merge(workflows::router(state.clone()))
         .merge(timers::router(state.clone()))
         .merge(kb::router(state.clone()))
+        .merge(settings::router(state.clone()))
         .route("/projects/{id}/files/{*path}", get(serve_project_file))
         .route("/projects/{id}/app/{*path}", any(proxy_to_service).with_state(state.clone()))
         .route("/projects/{id}/app/", any(proxy_to_service_root).with_state(state))