feat: cron jobs — daily summary, speaker clustering, clip purge

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/cron/purge_clips.py

@@ -0,0 +1,31 @@
+import sqlite3
+from datetime import datetime, timedelta
+from pathlib import Path
+from app.shared.config import Settings
+
+
+def purge_old_clips(today: str, settings: Settings, db: sqlite3.Connection) -> None:
+    cutoff = datetime.strptime(today, "%Y-%m-%d") - timedelta(days=settings.clip_retention_days)
+    clips_root = Path(settings.clips_dir)
+    if not clips_root.exists():
+        return
+    for date_dir in clips_root.iterdir():
+        if not date_dir.is_dir():
+            continue
+        try:
+            dir_date = datetime.strptime(date_dir.name, "%Y-%m-%d")
+        except ValueError:
+            continue
+        if dir_date < cutoff:
+            for wav in date_dir.glob("*.wav"):
+                wav.unlink()
+            try:
+                date_dir.rmdir()
+            except OSError:
+                pass
+    cutoff_str = cutoff.strftime("%Y-%m-%d")
+    db.execute(
+        "UPDATE utterances SET audio_clip_path=NULL WHERE date(start_time) < ?",
+        (cutoff_str,),
+    )
+    db.commit()