fix(alerts): webhook retry + dedupe (resolves §6.2)

_send_webhook:
- Dedupe: skip if alert.webhook_sent is already True (guards against
  repeated check_alerts ticks re-sending the same alert).
- Retry: up to 3 attempts with exponential backoff (1s, 2s) before
  giving up. webhook_sent=True is persisted only on success.

Two xfail guards in test_openclaw_client_and_webhook now pass (876/4 xfail).

backend/agenteval/intelligent_eval/alerts.py

@@ -151,12 +151,22 @@ class AlertManager:
 
         return alert
 
-    def _send_webhook(self, alert: AlertHistoryDB) -> None:
+    def _send_webhook(self, alert: AlertHistoryDB, max_retries: int = 3) -> None:
-        """Send webhook notification."""
+        """Send webhook with retry and dedupe.
+
+        P1 真问题修复（§6.2）:
+          - **Dedupe**: if ``alert.webhook_sent`` is already True, skip — guards
+            against repeated calls for the same alert (e.g. consecutive
+            ``check_alerts`` ticks).
+          - **Retry**: attempt the POST up to ``max_retries`` times with
+            exponential backoff (1s, 2s) before giving up. Persist
+            ``webhook_sent=True`` only on success.
+        """
         if not self.webhook_url:
             return
+        if alert.webhook_sent:
+            return
 
-        try:
         payload = {
             "alert_id": alert.id,
             "alert_type": alert.alert_type,
@@ -167,15 +177,23 @@ class AlertManager:
             "timestamp": alert.created_at.isoformat(),
         }
 
+        import time
+
+        last_err: Exception | None = None
+        for attempt in range(max_retries):
+            try:
                 response = httpx.post(self.webhook_url, json=payload, timeout=5.0)
                 response.raise_for_status()
-
                 alert.webhook_sent = True
                 self.session.commit()
-
+                _logger.info(f"Webhook sent for alert {alert.id} (attempt {attempt + 1})")
-            _logger.info(f"Webhook sent for alert {alert.id}")
+                return
             except Exception as e:
-            _logger.error(f"Failed to send webhook: {e}")
+                last_err = e
+                if attempt < max_retries - 1:
+                    time.sleep(2 ** attempt)
+
+        _logger.error(f"Failed to send webhook for alert {alert.id} after {max_retries} attempts: {last_err}")
 
     def get_alert_history(self, limit: int = 100) -> list[AlertHistoryDB]:
         """Get alert history.

tests/unit/test_openclaw_client_and_webhook.py

@@ -139,14 +139,6 @@ def test_webhook_failure_does_not_raise_or_mark_sent(db_session: Session):
     assert alert.webhook_sent is False
 
 
-@pytest.mark.xfail(
-    reason=(
-        "Known gap: webhook has no retry. _send_webhook swallows the first "
-        "failure and leaves webhook_sent=False; no follow-up attempt is made. "
-        "Tracked in .scratch/v111-architecture-scan.md."
-    ),
-    strict=False,
-)
 def test_webhook_retries_on_failure(db_session: Session):
     alert = _make_alert(db_session)
     fake_resp = MagicMock(); fake_resp.raise_for_status = MagicMock()
@@ -160,13 +152,6 @@ def test_webhook_retries_on_failure(db_session: Session):
     assert alert.webhook_sent is True
 
 
-@pytest.mark.xfail(
-    reason=(
-        "Known gap: no dedupe — every check_alerts trigger re-sends webhook "
-        "for the same alert. Tracked in .scratch/v111-architecture-scan.md."
-    ),
-    strict=False,
-)
 def test_webhook_dedupes_repeat_triggers(db_session: Session):
     """Calling _send_webhook twice on the same alert must POST at most once."""
     alert = _make_alert(db_session)