fix(automation): enforce durable alert closure

Restore D037 durable incident readback without weakening database failure semantics.

Fence Agent99 dispatch and terminal learning to canonical identities, durable leases, verifier receipts, and reconciler-owned checkpoints.

Drain backup and restore legacy receipts in bounded cohorts with strict transport, claim, projection, and no-false-green controls.

Keep SSH service refusal visible while separating it from broker network-policy reachability.

apps/api/src/utils/incident_converter.py

@@ -27,6 +27,7 @@ from src.models.incident import (
     IncidentStatus,
     Severity,
     Signal,
+    parse_signal_source,
 )
 
 logger = structlog.get_logger(__name__)
@@ -83,12 +84,10 @@ def brain_to_local(brain_incident: Any) -> Incident:
             except ValueError:
                 sig_severity = Severity.P2
 
-            # BrainSignal.source 是 str，LocalSignal.source 是 Literal
-            # 使用 getattr 確保不因 BrainSignal 欄位增減而崩潰
-            source = getattr(brain_signal, "source", "alertmanager")
-            valid_sources = {"prometheus", "signoz", "alertmanager", "manual", "telegram"}
-            if source not in valid_sources:
-                source = "alertmanager"
+            # Preserve repo-owned producer provenance across the package
+            # boundary. Unknown values fail closed instead of being mislabeled
+            # as Alertmanager and later poisoning the durable read model.
+            source = parse_signal_source(getattr(brain_signal, "source", ""))
 
             local_signals.append(
                 Signal(