chore: import upstream snapshot with attribution

tests/integration/api/conftest.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import pytest
+
+
+def dedupe_preregistered_groups() -> None:
+    """Keep API integration route registration isolated across test modules."""
+    from langbot.pkg.api.http.controller import group
+
+    seen: set[tuple[str, str]] = set()
+    unique_groups = []
+    for group_cls in group.preregistered_groups:
+        key = (group_cls.name, group_cls.path)
+        if key in seen:
+            continue
+        seen.add(key)
+        unique_groups.append(group_cls)
+
+    group.preregistered_groups[:] = unique_groups
+
+
+@pytest.fixture(scope='module')
+def http_controller_cls(mock_circular_import_chain):
+    """Import HTTPController under each module's circular-import isolation."""
+    from langbot.pkg.api.http.controller.main import HTTPController
+
+    dedupe_preregistered_groups()
+    return HTTPController