Merge branch 'feat/session-branch-selection' into dev

Resolved conflicts:
- Moved branch selection UI from inline sessions.tsx to CreateSessionForm component
- Integrated branch dropdown and new branch creation into CreateSessionForm
- Removed duplicate branch state management from sessions.tsx

All branch selection tests pass (7/7).

apps/api/tests/integration/test_tool_types_api.py

@@ -98,7 +98,6 @@ def _insert_tool_type(
     name: str,
     display_name: str,
     compose_template: str,
-    is_builtin: bool = False,
     created_by_id: str | None = None,
 ) -> None:
     async def _run() -> None:
@@ -120,7 +119,6 @@ def _insert_tool_type(
                 description="A test tool type",
                 compose_template=compose_template,
                 required_variables=["REPO_PATH", "TOOL_NAME"],
-                is_builtin=is_builtin,
                 created_by_id=uuid.UUID(created_by_id) if created_by_id else None,
             )
             await session.merge(tool_type)
@@ -234,7 +232,6 @@ def test_create_tool_type_successfully() -> None:
     assert data["name"] == "my-custom-tool"
     assert data["display_name"] == "My Custom Tool"
     assert data["description"] == "A custom development tool"
-    assert data["is_builtin"] == False
     assert data["created_by_id"] == user_id
     assert "id" in data
 
@@ -376,28 +373,7 @@ def test_update_tool_type_not_found() -> None:
     assert response.status_code == 404
 
 
-@pytest.mark.integration
-def test_update_builtin_tool_type_fails() -> None:
-    _prepare_test_db()
-    user_id = "11111111-1111-1111-1111-111111111111"
-    tool_type_id = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
-    _insert_user(user_id)
-    _insert_tool_type(
-        tool_type_id,
-        "builtin-tool",
-        "Built-in Tool",
-        "version: '3.8'\nservices:\n  app:\n    image: builtin",
-        is_builtin=True,
-    )
-    
-    app = _load_app()
-    client = TestClient(app)
-    client.cookies.set("access_token", _mint_token(user_id))
 
-    payload = {"display_name": "Updated"}
-    response = client.put(f"/tool-types/{tool_type_id}", json=payload)
-    
-    assert response.status_code == 403
 
 
 @pytest.mark.integration
@@ -442,53 +418,4 @@ def test_delete_tool_type_not_found() -> None:
     assert response.status_code == 404
 
 
-@pytest.mark.integration
-def test_delete_builtin_tool_type_fails() -> None:
-    _prepare_test_db()
-    user_id = "11111111-1111-1111-1111-111111111111"
-    tool_type_id = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
-    _insert_user(user_id)
-    _insert_tool_type(
-        tool_type_id,
-        "builtin-tool",
-        "Built-in Tool",
-        "version: '3.8'\nservices:\n  app:\n    image: builtin",
-        is_builtin=True,
-    )
-    
-    app = _load_app()
-    client = TestClient(app)
-    client.cookies.set("access_token", _mint_token(user_id))
 
-    response = client.delete(f"/tool-types/{tool_type_id}")
-    
-    assert response.status_code == 403
-
-
-@pytest.mark.integration
-def test_builtin_tool_types_seeded_on_startup() -> None:
-    _prepare_test_db()
-    user_id = "11111111-1111-1111-1111-111111111111"
-    _insert_user(user_id)
-    
-    # Load app triggers startup event which seeds built-in types
-    app = _load_app()
-    client = TestClient(app)
-    client.cookies.set("access_token", _mint_token(user_id))
-
-    response = client.get("/tool-types")
-    
-    assert response.status_code == 200
-    data = response.json()
-    
-    # Check that built-in types exist
-    builtin_names = [t["name"] for t in data if t["is_builtin"]]
-    assert "code-server" in builtin_names
-    assert "jupyter-notebook" in builtin_names
-    
-    # Verify built-in types have correct attributes
-    code_server = next((t for t in data if t["name"] == "code-server"), None)
-    assert code_server is not None
-    assert code_server["display_name"] == "VS Code Server"
-    assert "services" in code_server["compose_template"]
-    assert code_server["required_variables"] == ["REPO_PATH", "TOOL_NAME"]