fix(place-orders): two-call refresh + SELL recovery test

[suhailkakar]

Note

Medium Risk
Changes the order placement flow to conditionally submit on-chain approval transactions and retry the order on specific 400 rejections, which can affect trading behavior and trigger side effects (approvals/relayer calls). Test coverage is added, but the logic depends on matching a backend error string and new side-effect endpoints.

Overview
Adds post_order_with_allowance_recovery (async + sync) to retry POST /order when the API rejects with an allowance/balance 400 error: it checks current spender allowance, submits the appropriate approval (approve_erc20 for BUY, approve_erc1155_for_all for SELL), performs a two-call allowance refresh (/balance-allowance/update then /balance-allowance), and retries once.

Removes the previous preflight ensure_order_allowance check during signing, refactors allowance helpers to expose fetch_current_*_allowance utilities (including side/token-specific queries), and updates/expands unit tests to cover BUY/SELL recovery behavior and confirm create_*_order no longer hits allowance endpoints.

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