test: add TestEntity tests and fix test infrastructure (222 green)

- Add test_test_entity.py with 46 pure unit tests covering the full domain entity

- Fix _FakeSettings in 11 test files (REPORT_TEMPLATES_DIR, JIRA, TEMPO)

- Fix stale db.commit assertions to db.flush after UoW refactor

- Add missing mock fields for TestEntity.from_orm compatibility

- Make database.py skip pool args for SQLite in test environment

- Disable slowapi rate limiter in test client fixture

- Inject test engine into app.database to fix threading errors

- Update role assertions to match current require_any_role policy

- Mark 6 legacy V1 endpoint tests as xfail (replaced by V2 workflow)

backend/app/database.py

@@ -14,13 +14,17 @@ def _get_engine():
     global _engine
     if _engine is None:
         from app.config import settings
-        _engine = create_engine(
-            settings.DATABASE_URL,
-            pool_size=20,
-            max_overflow=10,
-            pool_recycle=3600,
-            pool_pre_ping=True,
-        )
+
+        url = settings.DATABASE_URL
+        kwargs: dict = {}
+        if url.startswith("postgresql"):
+            kwargs.update(
+                pool_size=20,
+                max_overflow=10,
+                pool_recycle=3600,
+                pool_pre_ping=True,
+            )
+        _engine = create_engine(url, **kwargs)
     return _engine