feat(feishu): render new session divider

maintainer edit: remove out-of-scope reasoning panel changes and keep this PR focused on the /new session divider.

nanobot/channels/feishu.py

@@ -25,6 +25,7 @@ from nanobot.bus.events import OutboundMessage
 from nanobot.bus.outbound_events import ProgressEvent
 from nanobot.bus.queue import MessageBus
 from nanobot.channels.base import BaseChannel
+from nanobot.command.router import normalize_command_text
 from nanobot.config.paths import get_media_dir
 from nanobot.config.schema import Base
 from nanobot.utils.helpers import safe_filename
@@ -555,6 +556,10 @@ def _qr_register_inner(
 
 
 _STREAM_ELEMENT_ID = "streaming_md"
+_NEW_SESSION_DIVIDER_CONTENT = json.dumps({
+    "type": "divider",
+    "params": {"divider_text": {"text": "New session started."}},
+})
 
 
 @dataclass
@@ -2010,6 +2015,14 @@ class FeishuChannel(BaseChannel):
                     )
                 return
 
+            if (
+                msg.content.strip() == "New session started."
+                and msg.metadata.get("chat_type") == "p2p"
+                and not msg.media
+                and not msg.buttons
+            ):
+                return
+
             # Determine whether the first message should quote the user's message.
             # Only the very first send (media or text) in this call uses reply; subsequent
             # chunks/media fall back to plain create to avoid redundant quote bubbles.
@@ -2260,6 +2273,17 @@ class FeishuChannel(BaseChannel):
             if not content and not media_paths:
                 return
 
+            if chat_type == "p2p" and normalize_command_text(content).lower() == "/new":
+                loop = asyncio.get_running_loop()
+                await loop.run_in_executor(
+                    None,
+                    self._send_message_sync,
+                    "open_id",
+                    sender_id,
+                    "system",
+                    _NEW_SESSION_DIVIDER_CONTENT,
+                )
+
             # Build session key for conversation isolation.
             # If topic_isolation is True: each topic gets its own session via root_id/message_id.
             # If topic_isolation is False: all messages in group share the same session.

tests/channels/test_feishu_reply.py

@@ -550,6 +550,64 @@ async def test_on_message_no_extra_api_call_when_no_parent_id() -> None:
     assert len(captured) == 1
 
 
+@pytest.mark.parametrize(("chat_type", "group_policy", "should_send"), [
+    ("p2p", "mention", True),
+    ("group", "open", False),
+])
+@pytest.mark.asyncio
+async def test_on_message_new_system_divider_only_in_p2p(
+    chat_type: str,
+    group_policy: str,
+    should_send: bool,
+) -> None:
+    channel = _make_feishu_channel(group_policy=group_policy)
+    channel._processed_message_ids.clear()
+    channel._send_message_sync = MagicMock(return_value="om_system")
+    channel._handle_message = AsyncMock()
+
+    with patch.object(channel, "_add_reaction", return_value=None):
+        await channel._on_message(_make_feishu_event(
+            chat_type=chat_type,
+            content='{"text": "/new"}',
+        ))
+
+    channel._handle_message.assert_awaited_once()
+    assert channel._handle_message.call_args.kwargs["content"] == "/new"
+    if not should_send:
+        channel._send_message_sync.assert_not_called()
+        return
+    _, receive_id, msg_type, content = channel._send_message_sync.call_args.args
+    assert receive_id == "ou_alice"
+    assert msg_type == "system"
+    assert json.loads(content)["type"] == "divider"
+
+
+@pytest.mark.asyncio
+async def test_send_new_session_text_suppressed_in_p2p_only() -> None:
+    p2p = _make_feishu_channel()
+    p2p._send_message_sync = MagicMock()
+
+    await p2p.send(OutboundMessage(
+        channel="feishu",
+        chat_id="ou_alice",
+        content="New session started.",
+        metadata={"chat_type": "p2p"},
+    ))
+
+    group = _make_feishu_channel()
+    group._send_message_sync = MagicMock(return_value="om_text")
+
+    await group.send(OutboundMessage(
+        channel="feishu",
+        chat_id="oc_group",
+        content="New session started.",
+        metadata={"chat_type": "group"},
+    ))
+
+    p2p._send_message_sync.assert_not_called()
+    assert group._send_message_sync.call_args.args[2] == "text"
+
+
 @pytest.mark.asyncio
 async def test_on_message_strips_required_leading_bot_mention_for_commands() -> None:
     channel = _make_feishu_channel(group_policy="mention")