feat(cli): watch files with event streams

- Add a private SSE endpoint that emits file change events for authenticated clients.
- Replace the watch sleep loop with watchdog local file events and remote SSE triggers.
- Debounce local event bursts and keep watch running after transient sync failures.
- Add watchdog as a standalone CLI dependency and cover watch behavior in tests.
- Bump NanoShare to 1.25.0 and the standalone CLI to 0.4.0.

run.py

@@ -13,6 +13,7 @@ from routes import (
   upload_bp,
   cli_auth_bp,
   api_download_bp,
+  api_events_bp,
   health_bp
 )
 from routes.api.link import link_bp as servicelink_bp
@@ -25,6 +26,7 @@ app.register_blueprint(side_main_bp)
 app.register_blueprint(upload_bp)
 app.register_blueprint(cli_auth_bp)
 app.register_blueprint(api_download_bp)
+app.register_blueprint(api_events_bp)
 
 # ServiceLink node-to-node mesh endpoint (POST /rpc)
 app.register_blueprint(servicelink_bp)