Add watch-folder mode and wire MCP/watcher into entrypoint

- New watcher.py: polls WATCH_DIR, enqueues transcription+summary via Celery.
- New process_watch_file_task in tasks.py.
- Updated __main__.py: WebUI always runs; MCP and watcher run in parallel when enabled.

scraibe/watcher.py

@@ -0,0 +1,100 @@
+"""
+Watch-folder mode for ScrAIbe.
+
+Monitors a folder for audio files. For each file:
+- Transcribes + summarizes
+- Emails results
+- Deletes source file
+
+Configuration (env):
+- WATCH_ENABLED: "true"/"false" (default: false)
+- WATCH_DIR: directory to watch (required if enabled)
+- WATCH_EMAIL_TO: destination email (required if enabled)
+- WATCH_POLL_INTERVAL: seconds between scans (default: 10)
+- WATCH_DELETE_ON_SUCCESS: "true"/"false" (default: true)
+"""
+
+import os
+import time
+import logging
+import threading
+from pathlib import Path
+
+logger = logging.getLogger("scraibe.watcher")
+
+AUDIO_EXTENSIONS = {
+    ".wav",
+    ".mp3",
+    ".flac",
+    ".m4a",
+    ".ogg",
+    ".webm",
+    ".mp4",
+}
+
+
+def _is_audio(path: Path) -> bool:
+    return path.is_file() and path.suffix.lower() in AUDIO_EXTENSIONS
+
+
+def _enqueue_file(file_path: Path):
+    """
+    Enqueue a file for transcription + summarization via Celery.
+    """
+    from .tasks import process_watch_file_task
+
+    try:
+        process_watch_file_task.delay(str(file_path))
+    except Exception as e:
+        logger.error("Failed to enqueue watch file %s: %s", file_path, e)
+
+
+def _scan_directory(watch_dir: Path):
+    """
+    Scan directory and enqueue all audio files.
+    """
+    if not watch_dir.is_dir():
+        logger.warning("WATCH_DIR does not exist or is not a directory: %s", watch_dir)
+        return
+
+    for p in watch_dir.iterdir():
+        if _is_audio(p):
+            logger.info("Found audio file in WATCH_DIR: %s", p)
+            _enqueue_file(p)
+
+
+def start_watcher():
+    """
+    Start watch-folder loop in a background thread.
+    """
+    enabled = os.getenv("WATCH_ENABLED", "false").strip().lower() in ("true", "1", "yes")
+    if not enabled:
+        return
+
+    watch_dir = os.getenv("WATCH_DIR")
+    if not watch_dir:
+        logger.warning("WATCH_ENABLED is true but WATCH_DIR is not set. Watcher disabled.")
+        return
+
+    email_to = os.getenv("WATCH_EMAIL_TO")
+    if not email_to:
+        logger.warning("WATCH_ENABLED is true but WATCH_EMAIL_TO is not set. Watcher disabled.")
+        return
+
+    interval = float(os.getenv("WATCH_POLL_INTERVAL", "10"))
+
+    watch_path = Path(watch_dir).expanduser().resolve()
+    watch_path.mkdir(parents=True, exist_ok=True)
+
+    logger.info("Starting watch-folder: dir=%s, email=%s, interval=%s", watch_dir, email_to, interval)
+
+    def _loop():
+        while True:
+            try:
+                _scan_directory(watch_path)
+            except Exception as e:
+                logger.error("Error scanning WATCH_DIR: %s", e)
+            time.sleep(interval)
+
+    t = threading.Thread(target=_loop, daemon=True)
+    t.start()