feat: add vault file system watcher with debounced sync

src/companion/indexer_daemon/watcher.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+import time
+from pathlib import Path
+
+from watchdog.events import FileSystemEventHandler
+from watchdog.observers import Observer
+
+from companion.config import load_config
+from companion.rag.indexer import Indexer
+from companion.rag.vector_store import VectorStore
+
+
+class VaultEventHandler(FileSystemEventHandler):
+    def __init__(self, indexer: Indexer, debounce_seconds: float = 5.0):
+        self.indexer = indexer
+        self.debounce_seconds = debounce_seconds
+        self._last_sync = 0.0
+
+    def on_any_event(self, event):
+        if event.is_directory:
+            return
+        if not event.src_path.endswith(".md"):
+            return
+        now = time.time()
+        if now - self._last_sync < self.debounce_seconds:
+            return
+        self._last_sync = now
+        try:
+            self.indexer.sync()
+        except Exception as exc:
+            print(f"Sync failed: {exc}")
+
+
+def start_watcher(config_path: str = "config.json") -> None:
+    config = load_config(config_path)
+    store = VectorStore(
+        uri=config.rag.vector_store.path, dimensions=config.rag.embedding.dimensions
+    )
+    indexer = Indexer(config, store)
+    handler = VaultEventHandler(indexer)
+    observer = Observer()
+    observer.schedule(handler, str(config.vault.path), recursive=True)
+    observer.start()
+    print(f"Watching {config.vault.path} for changes...")
+    try:
+        while True:
+            time.sleep(1)
+    except KeyboardInterrupt:
+        observer.stop()
+    observer.join()
+
+
+if __name__ == "__main__":
+    start_watcher()