feat(governance): unify durable event retention

tests/fixtures/architecture/dependency-baseline.json

@@ -13,8 +13,8 @@
     "runtime_to_db": [],
     "workflow_to_db": []
   },
-  "edge_count": 6767,
-  "edge_sha256": "659804b4d1c0f3ff4d96e8c9a059df0afb74c91f368a73188c740558114efa61",
+  "edge_count": 6773,
+  "edge_sha256": "3ba25180753ef7e15d9d08b7af25b66191306e8c0b465a27bed5613ed8d30c5d",
   "edges": [
     "app -> app.runtime",
     "app -> app.runtime.compat",
@@ -3724,11 +3724,17 @@
     "app.db.health -> app.db",
     "app.db.health -> app.db.session",
     "app.db.maintenance -> app.db",
+    "app.db.maintenance -> app.db.base",
     "app.db.maintenance -> app.db.models",
+    "app.db.maintenance -> app.db.models.agentchat",
+    "app.db.maintenance -> app.db.models.agenttask",
+    "app.db.maintenance -> app.db.models.agenttaskrun",
     "app.db.maintenance -> app.db.models.downloadfailure",
     "app.db.maintenance -> app.db.models.downloadhistory",
     "app.db.maintenance -> app.db.models.message",
+    "app.db.maintenance -> app.db.models.outbox",
     "app.db.maintenance -> app.db.models.siteuserdata",
+    "app.db.maintenance -> app.db.models.subscribehistory",
     "app.db.maintenance -> app.db.models.transferhistory",
     "app.db.maintenance -> app.db.uow",
     "app.db.models -> app.db",