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.

tests/test_nanoshare_cli.py

@@ -11,6 +11,7 @@ from nanoshare_client.auth import _CallbackServer
 from nanoshare_client.completion import script as completion_script
 from nanoshare_client.ignore import load_ignore_patterns, is_ignored
 from nanoshare_client.table import format_table
+from nanoshare_client.watch import _is_relevant_path
 
 class FakeClient:
   def __init__(self):
@@ -268,6 +269,44 @@ def test_default_ignore_patterns_skip_common_generated_files(tmp_path):
   assert is_ignored('nested/Thumbs.db', patterns)
   assert not is_ignored('docs/note.txt', patterns)
 
+def test_watch_loop_retries_after_sync_error(monkeypatch, tmp_path):
+  from nanoshare_client import watch as watch_module
+
+  calls = []
+
+  class FakeFlag:
+    def __init__(self):
+      pass
+
+    def clear(self):
+      pass
+
+    def wait(self, timeout):
+      return False
+
+  def fake_sync(args):
+    calls.append(args.folder)
+    if len(calls) == 1:
+      return 1
+    raise KeyboardInterrupt
+
+  monkeypatch.setattr(watch_module, '_ChangeFlag', FakeFlag)
+  monkeypatch.setattr(watch_module, '_watchdog_observer', lambda *args: None)
+  args = type('Args', (), {'folder': str(tmp_path), 'ignore': [], 'interval': 0.1})()
+
+  code = watch_module.watch_loop(args, fake_sync)
+
+  assert code == 0
+  assert calls == [str(tmp_path), str(tmp_path)]
+
+def test_watch_relevance_ignores_sync_state_and_default_ignores(tmp_path):
+  patterns = load_ignore_patterns(tmp_path)
+
+  assert _is_relevant_path(tmp_path, str(tmp_path / 'note.txt'), patterns)
+  assert not _is_relevant_path(tmp_path, str(tmp_path / '.nanoshare-sync' / 'state.json'), patterns)
+  assert not _is_relevant_path(tmp_path, str(tmp_path / '.comments' / 'comment.xml'), patterns)
+  assert not _is_relevant_path(tmp_path, str(tmp_path / '.env'), patterns)
+
 def test_completion_scripts_include_commands():
   zsh = completion_script('zsh')
   bash = completion_script('bash')