Preserve tenant module entitlement state

tests/test_tenant_lifecycle.py

@@ -12,6 +12,7 @@ from govoplan_tenancy.backend.api.v1.routes import (
     _require_tenant_update_permissions,
 )
 from govoplan_tenancy.backend.api.v1.schemas import TenantUpdateRequest
+from govoplan_core.core.module_entitlements import MODULE_ENTITLEMENTS_KEY
 from govoplan_tenancy.backend.lifecycle import (
     TENANT_EVENT_CREATED,
     TENANT_EVENT_DELETION_REQUESTED,
@@ -121,6 +122,26 @@ class TenantUpdateHelperTests(unittest.TestCase):
         self.assertEqual("en", tenant.default_locale)
         self.assertEqual({"theme": "contrast"}, tenant.settings)
 
+    def test_tenant_content_update_preserves_reserved_module_entitlements(self) -> None:
+        entitlement = {"schema_version": 1, "revision": 4}
+        tenant = SimpleNamespace(
+            name="Old",
+            description=None,
+            default_locale="en",
+            settings={MODULE_ENTITLEMENTS_KEY: entitlement, "theme": "old"},
+        )
+        payload = TenantUpdateRequest(
+            settings={
+                "theme": "contrast",
+                MODULE_ENTITLEMENTS_KEY: {"revision": 999},
+            }
+        )
+
+        _apply_tenant_content_updates(tenant, payload)  # type: ignore[arg-type]
+
+        self.assertEqual("contrast", tenant.settings["theme"])
+        self.assertEqual(entitlement, tenant.settings[MODULE_ENTITLEMENTS_KEY])
+
     def test_tenant_status_update_prevents_suspending_current_tenant(self) -> None:
         tenant = SimpleNamespace(id="tenant-1", is_active=True)
         principal = FakePrincipal({"system:tenants:suspend"}, tenant_id="tenant-1")