fix(client): point Combos RFQ endpoints at polymarket.com domains

[cesarenaldi]

Summary

Switch the Combos RFQ production endpoints from the temporary .sh domains to the new .com domains:

• REST: https://combos-rfq-api.polymarket.sh -> https://combos-rfq-api.polymarket.com
• Quoter WS: wss://combos-rfq-gateway-quoter.polymarket.sh/ws/rfq -> wss://combos-rfq-gateway-quoter.polymarket.com/ws/rfq

Verification

• uv run pytest tests/unit: 1694 passed
• Live smoke: PublicClient().list_combo_markets() against combos-rfq-api.polymarket.com returns combo markets
• WS handshake on combos-rfq-gateway-quoter.polymarket.com/ws/rfq returns 101 Switching Protocols

---

Note

Low Risk
Config-only hostname swap for RFQ API and WS; behavior unchanged aside from which host clients connect to.

Overview
Updates production Combos RFQ configuration in environments.py so clients use the permanent .com hosts instead of temporary .sh URLs.

REST rfq_url on PRODUCTION is now https://combos-rfq-api.polymarket.com. The default quoter WebSocket on Environment is now wss://combos-rfq-gateway-quoter.polymarket.com/ws/rfq. No other endpoints or contract addresses change.

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