Feature/feishu receive file (#1608)

* feat(feishu): add channel file materialization hook for inbound messages

- Introduce Channel.receive_file(msg, thread_id) as a base method for file materialization; default is no-op.
- Implement FeishuChannel.receive_file to download files/images from Feishu messages, save to sandbox, and inject virtual paths into msg.text.
- Update ChannelManager to call receive_file for any channel if msg.files is present, enabling downstream model access to user-uploaded files.
- No impact on Slack/Telegram or other channels (they inherit the default no-op).

* style(backend): format code with ruff for lint compliance

- Auto-formatted packages/harness/deerflow/agents/factory.py and tests/test_create_deerflow_agent.py using `ruff format`
- Ensured both files conform to project linting standards
- Fixes CI lint check failures caused by code style issues

* fix(feishu): handle file write operation asynchronously to prevent blocking

* fix(feishu): rename GetMessageResourceRequest to _GetMessageResourceRequest and remove redundant code

* test(feishu): add tests for receive_file method and placeholder replacement

* fix(manager): remove unnecessary type casting for channel retrieval

* fix(feishu): update logging messages to reflect resource handling instead of image

* fix(feishu): sanitize filename by replacing invalid characters in file uploads

* fix(feishu): improve filename sanitization and reorder image key handling in message processing

* fix(feishu): add thread lock to prevent filename conflicts during file downloads

* fix(test): correct bad merge in test_feishu_parser.py

* chore: run ruff and apply formatting cleanup
fix(feishu): preserve rich-text attachment order and improve fallback filename handling

backend/tests/test_feishu_parser.py

@@ -1,11 +1,20 @@
+import asyncio
 import json
-from unittest.mock import MagicMock
+from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
 from app.channels.commands import KNOWN_CHANNEL_COMMANDS
 from app.channels.feishu import FeishuChannel
-from app.channels.message_bus import MessageBus
+from app.channels.message_bus import InboundMessage, MessageBus
+
+
+def _run(coro):
+    loop = asyncio.new_event_loop()
+    try:
+        return loop.run_until_complete(coro)
+    finally:
+        loop.close()
 
 
 def test_feishu_on_message_plain_text():
@@ -71,6 +80,64 @@ def test_feishu_on_message_rich_text():
         assert "\n\n" in parsed_text
 
 
+def test_feishu_receive_file_replaces_placeholders_in_order():
+    async def go():
+        bus = MessageBus()
+        channel = FeishuChannel(bus, {"app_id": "test", "app_secret": "test"})
+
+        msg = InboundMessage(
+            channel_name="feishu",
+            chat_id="chat_1",
+            user_id="user_1",
+            text="before [image] middle [file] after",
+            thread_ts="msg_1",
+            files=[{"image_key": "img_key"}, {"file_key": "file_key"}],
+        )
+
+        channel._receive_single_file = AsyncMock(side_effect=["/mnt/user-data/uploads/a.png", "/mnt/user-data/uploads/b.pdf"])
+
+        result = await channel.receive_file(msg, "thread_1")
+
+        assert result.text == "before /mnt/user-data/uploads/a.png middle /mnt/user-data/uploads/b.pdf after"
+
+    _run(go())
+
+
+def test_feishu_on_message_extracts_image_and_file_keys():
+    bus = MessageBus()
+    channel = FeishuChannel(bus, {"app_id": "test", "app_secret": "test"})
+
+    event = MagicMock()
+    event.event.message.chat_id = "chat_1"
+    event.event.message.message_id = "msg_1"
+    event.event.message.root_id = None
+    event.event.sender.sender_id.open_id = "user_1"
+
+    # Rich text with one image and one file element.
+    event.event.message.content = json.dumps(
+        {
+            "content": [
+                [
+                    {"tag": "text", "text": "See"},
+                    {"tag": "img", "image_key": "img_123"},
+                    {"tag": "file", "file_key": "file_456"},
+                ]
+            ]
+        }
+    )
+
+    with pytest.MonkeyPatch.context() as m:
+        mock_make_inbound = MagicMock()
+        m.setattr(channel, "_make_inbound", mock_make_inbound)
+        channel._on_message(event)
+
+        mock_make_inbound.assert_called_once()
+        files = mock_make_inbound.call_args[1]["files"]
+        assert files == [{"image_key": "img_123"}, {"file_key": "file_456"}]
+        assert "[image]" in mock_make_inbound.call_args[1]["text"]
+        assert "[file]" in mock_make_inbound.call_args[1]["text"]
+
+
 @pytest.mark.parametrize("command", sorted(KNOWN_CHANNEL_COMMANDS))
 def test_feishu_recognizes_all_known_slash_commands(command):
     """Every entry in KNOWN_CHANNEL_COMMANDS must be classified as a command."""