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_memory_queue_user_isolation.py

@@ -0,0 +1,38 @@
+"""Tests for user_id propagation through memory queue."""
+from unittest.mock import MagicMock, patch
+
+from deerflow.agents.memory.queue import ConversationContext, MemoryUpdateQueue
+
+
+def test_conversation_context_has_user_id():
+    ctx = ConversationContext(thread_id="t1", messages=[], user_id="alice")
+    assert ctx.user_id == "alice"
+
+
+def test_conversation_context_user_id_default_none():
+    ctx = ConversationContext(thread_id="t1", messages=[])
+    assert ctx.user_id is None
+
+
+def test_queue_add_stores_user_id():
+    q = MemoryUpdateQueue()
+    with patch.object(q, "_reset_timer"):
+        q.add(thread_id="t1", messages=["msg"], user_id="alice")
+    assert len(q._queue) == 1
+    assert q._queue[0].user_id == "alice"
+    q.clear()
+
+
+def test_queue_process_passes_user_id_to_updater():
+    q = MemoryUpdateQueue()
+    with patch.object(q, "_reset_timer"):
+        q.add(thread_id="t1", messages=["msg"], user_id="alice")
+
+    mock_updater = MagicMock()
+    mock_updater.update_memory.return_value = True
+    with patch("deerflow.agents.memory.updater.MemoryUpdater", return_value=mock_updater):
+        q._process_queue()
+
+    mock_updater.update_memory.assert_called_once()
+    call_kwargs = mock_updater.update_memory.call_args.kwargs
+    assert call_kwargs["user_id"] == "alice"