refactor(tests): reorganize tests into unittest/ and e2e/ directories

- Move all unit tests from tests/ to tests/unittest/
- Add tests/e2e/ directory for end-to-end tests
- Update conftest.py for new test structure
- Add new tests for auth dependencies, policies, route injection
- Add new tests for run callbacks, create store, execution artifacts
- Remove obsolete tests for deleted persistence layer

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/unittest/test_run_create_store.py

@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+from unittest.mock import AsyncMock
+
+import pytest
+
+from app.gateway.services.runs.store.create_store import AppRunCreateStore
+from deerflow.runtime.runs.types import RunRecord, RunStatus
+
+
+@pytest.mark.anyio
+async def test_create_run_syncs_thread_meta_assistant_id():
+    repo = AsyncMock()
+    thread_meta_storage = AsyncMock()
+    thread_meta_storage.ensure_thread.return_value.assistant_id = None
+
+    store = AppRunCreateStore(repo, thread_meta_storage=thread_meta_storage)
+    record = RunRecord(
+        run_id="run-1",
+        thread_id="thread-1",
+        assistant_id="lead_agent",
+        status=RunStatus.pending,
+        temporary=False,
+        multitask_strategy="reject",
+    )
+
+    await store.create_run(record)
+
+    repo.create.assert_awaited_once()
+    thread_meta_storage.ensure_thread.assert_awaited_once_with(
+        thread_id="thread-1",
+        assistant_id="lead_agent",
+    )
+    thread_meta_storage.sync_thread_assistant_id.assert_awaited_once_with(
+        thread_id="thread-1",
+        assistant_id="lead_agent",
+    )