Fix Python 3.10+/websockets compatibility, add CLI args and .gitignore

- ws/message.py, ws/server/ws_server_multi_user.py: drop the loop= kwarg
  and replace asyncio.wait(coroutines) with asyncio.gather(), both of
  which were removed/forbidden in Python 3.10+.
- brewpi/requirements.txt: pin websockets==10.4, the latest version that
  still supports this code's serve()/handler API.
- config.json.sim: move Model to the top level and add the missing gain
  field so it matches the schema brewpi.py and config.json.templ expect.
- brewpi/brewpi.py: add -c/-m/-s/-d CLI args for selecting config/model
  files, simulation mode, and debug.
- .gitignore: exclude __pycache__, logs, the local config.json, and
  editor/venv directories.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ws/message.py

@@ -35,7 +35,7 @@ class MessageDispatcher(IConnection):
 	def __init__(self, auto_subscribe=False, loop=None):
 		self.msg_handlers: MsgIo = []
 		self.state = None
-		self.state = asyncio.Queue(loop=loop)
+		self.state = asyncio.Queue()
 		self.auto_subscribe = auto_subscribe
 		self.loop = loop