test: massive coverage expansion — 15 new test modules + assistant tool fixes + orthogonal testing

- 10 translate plugin test files (100% coverage on 12 modules)
- assistant/handler tools: 85+ tests covering dispatch, registry, resolvers, routes, llm_planner, 13 tool handlers
- clean release: artifact_catalog_loader, mappers, approval, publication tests
- API routes: translate_helpers, validation_service extensions, datasets to 100%
- notifications: providers/service tests
- services: profile_preference_service
- docs/orthogonal-test-report.md — full speckit.tests audit
- Fixes: 3 git_base async mock failures, 4 assistant handler permission-check patches
- .gitignore: coverage artifacts

backend/tests/api/test_auth.py

@@ -228,9 +228,12 @@ class TestCallbackAdfs:
 
     def test_callback_success(self):
         """ADFS callback provisions user and returns token."""
-        mock_token = MagicMock()
-        mock_token.access_token = "adfs.token.xyz"
-        mock_token.token_type = "bearer"
+        from types import SimpleNamespace
+
+        mock_token = SimpleNamespace(
+            access_token="adfs.token.xyz",
+            token_type="bearer",
+        )
         mock_user_info = {"sub": "adfs-user", "email": "adfs@example.com"}
 
         mock_oauth = MagicMock()