feat: add config profiles

- Add ConfigProfile and ConfigProfileInclude data models with migrations
- Implement profile resolver service with ordered includes and merge rules
- Add profile CRUD API with validation, compatibility, and cycle detection
- Add instance API plumbing for profile selection on create/start/restart
- Add resolved profile preview and default resolution APIs
- Add frontend config profile API client and management UI
- Add launch/restart profile selection UI
- Add backend integration and unit tests (31 passing)

OpenSpec: add-config-profiles
Quality gates: ruff, TypeScript compile, 31 tests passing

apps/api/tests/conftest.py

@@ -47,10 +47,8 @@ def test_client() -> Generator[TestClient, None, None]:
     app.dependency_overrides[get_db_session] = override_get_db_session
     
     # Patch startup events to prevent PostgreSQL connection attempts
-    with patch("src.main.init_database") as mock_init, \
-         patch("src.main.seed_builtin_tool_types") as mock_seed:
+    with patch("src.main.init_database") as mock_init:
         mock_init.return_value = True
-        mock_seed.return_value = None
         
         try:
             with TestClient(app) as client:
@@ -61,6 +59,31 @@ def test_client() -> Generator[TestClient, None, None]:
             asyncio.run(engine.dispose())
 
 
+@pytest_asyncio.fixture
+async def db_session(test_client) -> AsyncGenerator[AsyncSession, None]:
+    """Provide an async database session for unit tests."""
+    # Get the override function from the test_client fixture
+    override_fn = app.dependency_overrides.get(get_db_session)
+    if override_fn:
+        gen = override_fn()
+        session = await gen.asend(None)
+        try:
+            yield session
+        finally:
+            await gen.aclose()
+    else:
+        # Fallback: create a new engine and session
+        engine = create_async_engine(
+            "sqlite+aiosqlite:///:memory:",
+            connect_args={"check_same_thread": False},
+        )
+        async with engine.begin() as conn:
+            await conn.run_sync(Base.metadata.create_all)
+        async with async_sessionmaker(engine, expire_on_commit=False)() as session:
+            yield session
+        await engine.dispose()
+
+
 @pytest.fixture
 def authenticated_client(test_client) -> Generator[TestClient, None, None]:
     """Provide an authenticated test client with a test user."""