fix(rfq): parse submission window rejections

[cesarenaldi]

Summary

• Replace the stale RFQ COMPETITION_WINDOW_CLOSED enum value with SUBMISSION_WINDOW_CLOSED.
• Allows RFQ error parsing to accept submission-window quote rejections.

Verification

• uv run ruff check .
• uv run pyright

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Note

Low Risk
Single enum member rename in public RFQ types; no logic changes beyond matching the API error string.

Overview
Updates RfqErrorCode in rfq.py by removing COMPETITION_WINDOW_CLOSED and adding SUBMISSION_WINDOW_CLOSED so RFQ quote rejections from the API match the enum used in _parse_error_code (via RfqErrorCode(value)).

Without this rename, submission-window rejections would surface as unknown error codes instead of typed RfqQuoteRejectedError (or related) with a recognized code.

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