fix(d3): systemischer Permission-Resolver-Bug behoben — DMS/Mail get_entity_models-Overrides ergänzt (dms_file/dms_folder/file/mail_account fehlten im ENTITY_MODELS-Mapping → ValueError bei allen Entity-Freigaben zur Laufzeit); pgvector-Extension in conftest db_setup verankert; test_permissions 22/22 grün; Resolver-Auflösung aller 4 Typen direkt bewiesen

app/plugins/builtins/mail/plugin.py

@@ -159,6 +159,12 @@ class MailPlugin(BasePlugin):
         contract_version="1.0.0",
     )
 
+    def get_entity_models(self) -> dict[str, type]:
+        """Entity types owned by Mail for the permission resolver."""
+        from app.plugins.builtins.mail.models import MailAccount
+
+        return {"mail_account": MailAccount}
+
     async def on_activate(
         self, db, service_container, event_bus
     ) -> None: