fix(rebase): remove duplicate definitions and update stale module paths

Rebase left duplicate function blocks in worker.py (triple human_message
write causing 3x user messages in /history), deps.py, and prompt.py.
Also update checkpointer imports from the old deerflow.agents.checkpointer
path to deerflow.runtime.checkpointer, and clean up orphaned feedback
props in the frontend message components.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/tests/test_checkpointer.py

@@ -178,7 +178,7 @@ class TestAsyncCheckpointer:
     @pytest.mark.anyio
     async def test_sqlite_creates_parent_dir_via_to_thread(self):
         """Async SQLite setup should move mkdir off the event loop."""
-        from deerflow.agents.checkpointer.async_provider import make_checkpointer
+        from deerflow.runtime.checkpointer.async_provider import make_checkpointer
 
         mock_config = MagicMock()
         mock_config.checkpointer = CheckpointerConfig(type="sqlite", connection_string="relative/test.db")
@@ -195,11 +195,11 @@ class TestAsyncCheckpointer:
         mock_module.AsyncSqliteSaver = mock_saver_cls
 
         with (
-            patch("deerflow.agents.checkpointer.async_provider.get_app_config", return_value=mock_config),
+            patch("deerflow.runtime.checkpointer.async_provider.get_app_config", return_value=mock_config),
             patch.dict(sys.modules, {"langgraph.checkpoint.sqlite.aio": mock_module}),
-            patch("deerflow.agents.checkpointer.async_provider.asyncio.to_thread", new_callable=AsyncMock) as mock_to_thread,
+            patch("deerflow.runtime.checkpointer.async_provider.asyncio.to_thread", new_callable=AsyncMock) as mock_to_thread,
             patch(
-                "deerflow.agents.checkpointer.async_provider.resolve_sqlite_conn_str",
+                "deerflow.runtime.checkpointer.async_provider.resolve_sqlite_conn_str",
                 return_value="/tmp/resolved/test.db",
             ),
         ):