feat(rfq): reintroduce confirmed trade broadcasts

[cesarenaldi]

Summary

• parse public RFQ_TRADE websocket frames as typed RfqTradeEvent session events
• align the public event with the gateway contract: requester_id replaces requestor_public_id
• omit settlement tx_hash from the public trade event; it remains available only in private RFQ_EXECUTION_UPDATE messages to the participating maker

Rollout

• pairs with https://github.com/Polymarket/combos-rfq/pull/110
• keep this draft until the gateway broadcast is deployed and the SDK release can include the matching wire contract

Verification

• ruff format --check .
• ruff check .
• strict Pyright over the changed RFQ files
• direct RFQ_TRADE parser smoke check
• the websocket integration test requires local POLYMARKET_PRIVATE_KEY credentials and remains covered by CI

[shazam8253]

Superseded by #112, which implements the same SDK support directly from main without depending on the reverted feature branch.