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_callbacks_builder.py

@@ -0,0 +1,66 @@
+from __future__ import annotations
+
+from langchain_core.messages import HumanMessage
+
+from deerflow.runtime.runs.callbacks.builder import build_run_callbacks
+from deerflow.runtime.runs.types import RunRecord, RunStatus
+
+
+def _record() -> RunRecord:
+    return RunRecord(
+        run_id="run-1",
+        thread_id="thread-1",
+        assistant_id=None,
+        status=RunStatus.pending,
+        temporary=False,
+        multitask_strategy="reject",
+        metadata={},
+        created_at="",
+        updated_at="",
+    )
+
+
+def test_build_run_callbacks_sets_first_human_message_from_string_content():
+    artifacts = build_run_callbacks(
+        record=_record(),
+        graph_input={"messages": [HumanMessage(content="hello world")]},
+        event_store=None,
+    )
+
+    assert artifacts.completion_data().first_human_message == "hello world"
+
+
+def test_build_run_callbacks_sets_first_human_message_from_content_blocks():
+    artifacts = build_run_callbacks(
+        record=_record(),
+        graph_input={
+            "messages": [
+                HumanMessage(
+                    content=[
+                        {"type": "text", "text": "hello "},
+                        {"type": "text", "text": "world"},
+                    ]
+                )
+            ]
+        },
+        event_store=None,
+    )
+
+    assert artifacts.completion_data().first_human_message == "hello world"
+
+
+def test_build_run_callbacks_sets_first_human_message_from_dict_payload():
+    artifacts = build_run_callbacks(
+        record=_record(),
+        graph_input={
+            "messages": [
+                {
+                    "role": "user",
+                    "content": [{"type": "text", "text": "hi from dict"}],
+                }
+            ]
+        },
+        event_store=None,
+    )
+
+    assert artifacts.completion_data().first_human_message == "hi from dict"