fix: normalize WebSocket /msgjoin channel and reject empty channels

/msgjoin was lowercasing the channel but not ensuring the leading '#'.
Use _clean_channel_list so bare channel names become valid '#channel'
names, and reject an empty/whitespace channel with a clear error.

Author: luni

dccbot/app.py

@@ -482,12 +482,14 @@ async def handle_ws_command(self, command: str | None, args: list[str], ws: web.
                     raise RuntimeError("Not enough arguments")
                 server = args.pop(0)
                 bot = await self.bot_manager.get_bot(server)
-                channel = args.pop(0)
+                channels = self._clean_channel_list([args.pop(0)])
+                if not channels:
+                    raise RuntimeError("Invalid channel")
                 target = args.pop(0).lower().strip()
                 await bot.queue_command({
                     "command": "send",
                     "user": target,
-                    "channels": [channel.lower().strip()],
+                    "channels": [channels[0]],
                     "message": " ".join(args),
                 })
             elif command == "info":

tests/unit/test_websocket.py

@@ -277,3 +277,17 @@ async def test_websocket_handler_msgjoin_command(ws_session):
     assert call_args["channels"] == ["#channel"]
     assert call_args["message"] == "hello world"
     await ws.close()
+
+
+@pytest.mark.asyncio
+async def test_websocket_handler_msgjoin_normalizes_channel(ws_session):
+    """Test websocket /msgjoin adds # to bare channel names."""
+    ws, mock_bot_manager = ws_session
+    mock_bot = MagicMock()
+    mock_bot.queue_command = AsyncMock()
+    mock_bot_manager.get_bot = AsyncMock(return_value=mock_bot)
+    await ws.send_str("/msgjoin server Channel target hello world")
+    await asyncio.sleep(0.1)
+    call_args = mock_bot.queue_command.call_args[0][0]
+    assert call_args["channels"] == ["#channel"]
+    await ws.close()