feat(ws): expose websocket proxy/connect options on Client

[Xuxchloris]

Fixes #143.

Problem

lark.ws.Client forces a direct WebSocket connection (on websockets >= 15 it explicitly passes proxy=None), with no supported way for applications behind an HTTP/HTTPS/SOCKS proxy to make the long-lived event WebSocket honor HTTP_PROXY/HTTPS_PROXY/ALL_PROXY/NO_PROXY — or to pass any custom websockets.connect() options. The only workaround was monkeypatching the private _ws_connect_kwargs.

Change

New optional ws_connect_kwargs parameter on Client.__init__:

• None (default): behavior is identical to today — direct connection, proxy=None forced on websockets >= 15.
• Provided: the forced direct-connect flag is dropped (so environment proxy discovery or an explicit proxy works) and the caller's values merge over SDK defaults.

The resolved kwargs are computed once per _connect() via Client._resolved_ws_connect_kwargs() and passed to websockets.connect().

Tests

lark_oapi/ws/tests/test_ws_connect_kwargs.py (5 tests):

• default preserves the historical direct-connect kwargs;
• explicit proxy wins over the forced proxy=None;
• empty dict opts into environment proxy discovery (no proxy key);
• caller values merge with SDK defaults;
• the websockets-signature detection still behaves as before.

Verification

• python -m pytest lark_oapi/ws/tests/test_ws_connect_kwargs.py test_redact_conn_url.py — 8/8 pass.