feat(webhook): dedup deliveries by delivery_id (M-7)

src/webhooks/plane.py

@@ -15,7 +15,9 @@ from ..db import (
     get_next_work_item_id,
     update_task_stage,
     enqueue_job,
+    insert_event_dedup,
 )
+from ._dedup import plane_delivery_id
 from ..stages import get_next_stage, get_agent_for_stage, get_qg_for_stage, get_previous_stage
 from ..qg.checks import QG_CHECKS
 from ..notifications import notify_stage_change, notify_qg_failure, notify_error
@@ -61,14 +63,18 @@ async def plane_webhook(request: Request):
 
     payload = json.loads(body)
 
-    # Log event
-    conn = get_db()
-    conn.execute(
-        "INSERT INTO events (source, event_type, payload) VALUES (?, ?, ?)",
-        ("plane", payload.get("event", "unknown"), body.decode()),
-    )
-    conn.commit()
-    conn.close()
+    # ORCH-5 (M-7): idempotent logging. Plane rarely sends a delivery header, so the
+    # delivery_id falls back to sha256("plane" + body) (a retried identical body maps
+    # to one id). INSERT OR IGNORE; a duplicate returns inserted=False -> log + return
+    # {"status":"duplicate"} WITHOUT dispatching. Runs AFTER HMAC and BEFORE the ORCH-6
+    # project filter, so a repeat does no extra work; the FIRST delivery of an unknown
+    # project still falls through to the filter below and returns {"status":"ignored"}.
+    event_type = payload.get("event", "unknown")
+    delivery_id = plane_delivery_id(request.headers, body)
+    inserted = insert_event_dedup("plane", event_type, body.decode(), delivery_id)
+    if not inserted:
+        logger.info(f"Plane webhook duplicate delivery_id={delivery_id}, skipping dispatch")
+        return {"status": "duplicate"}
 
     event = payload.get("event")
     action = payload.get("action", "")