Deduplicate listen events from multiple HA entities

When a track plays, multiple HA entities (Cast, WiFi, MA) all fire
the automation simultaneously, creating 3x duplicate listen events.
Now skips logging if the same track was recorded within the last 60s.

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

src/haunt_fm/api/history.py

@@ -36,4 +36,6 @@ async def receive_webhook(payload: WebhookPayload, session: AsyncSession = Depen
         listened_at=payload.listened_at,
         raw_payload=payload.model_dump(mode="json"),
     )
+    if event is None:
+        return {"ok": True, "duplicate": True}
     return {"ok": True, "track_id": event.track_id, "event_id": event.id}

src/haunt_fm/services/history_ingest.py

@@ -1,10 +1,13 @@
-from datetime import datetime
+import logging
+from datetime import datetime, timedelta, timezone
 
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from haunt_fm.models.track import ListenEvent, Track
 
+logger = logging.getLogger(__name__)
+
 
 def make_fingerprint(artist: str, title: str) -> str:
     return f"{artist.lower().strip()}::{title.lower().strip()}"
@@ -47,9 +50,22 @@ async def ingest_listen_event(
     source: str,
     listened_at: datetime,
     raw_payload: dict | None = None,
-) -> ListenEvent:
+) -> ListenEvent | None:
     track = await upsert_track(session, title, artist, album)
 
+    # Deduplicate: skip if this track was logged within the last 60 seconds.
+    # Multiple HA entities (Cast, WiFi, MA) fire simultaneously for the same play event.
+    cutoff = datetime.now(timezone.utc) - timedelta(seconds=60)
+    recent = await session.execute(
+        select(ListenEvent)
+        .where(ListenEvent.track_id == track.id)
+        .where(ListenEvent.listened_at > cutoff)
+        .limit(1)
+    )
+    if recent.scalar_one_or_none() is not None:
+        logger.debug("Skipping duplicate listen event for %s - %s", artist, title)
+        return None
+
     event = ListenEvent(
         track_id=track.id,
         source=source,