fix: Make watch setup resilient to unmounted paths

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

main.py

@@ -31,7 +31,7 @@ def trigger_scan():
 
 def add_watch_recursive(inotify, path, watch_flags, wd_to_path):
     """Walk a directory path and add watches recursively."""
-    try:
+    logging.info(f"Watching {path} and its subdirectories recursively.")
     for root, _, _ in os.walk(path):
         try:
             logging.info(f"Watching {root}")
@@ -39,8 +39,6 @@ def add_watch_recursive(inotify, path, watch_flags, wd_to_path):
             wd_to_path[wd] = root
         except OSError as e:
             logging.error(f"Error adding watch for {root}: {e}")
-    except FileNotFoundError:
-        logging.warning(f"Could not scan {path} as it was not found.")
 
 
 def main():
@@ -49,12 +47,16 @@ def main():
     wd_to_path = {}
 
     with INotify() as inotify:
-        for path in secrets.WATCH_PATHS:
-            logging.info(f"Watching {path} and its subdirectories recursively.")
-            add_watch_recursive(inotify, path, watch_flags, wd_to_path)
-
         try:
             while True:
+                watched_dirs = set(wd_to_path.values())
+                for path in secrets.WATCH_PATHS:
+                    if path not in watched_dirs:
+                        if os.path.exists(path):
+                            add_watch_recursive(inotify, path, watch_flags, wd_to_path)
+                        else:
+                            logging.warning(f"Watch path {path} does not exist. Will retry.")
+
                 events = inotify.read(timeout=1000)
                 if events:
                     scan_needed = False