Address all six low findings in audit 6b607200-d29f-4c7a-8476-0dca8091f48f against commit 0d9d440063465654f39ef7f3939b1b4d9c90c5f6 in one coherent change.

Specifically prevent the job-expiry/failure race; prevent a wrong pre-binding from losing a one-shot review answer; provide safe closure for an abandoned pending ask and an incident response for a retained answer from a compromised signer; prevent quoted-but-unspent IMD from becoming owner-sweepable; and add a caller-specified maximum price to paid requests. Preserve signed-answer binding, replay protection, receipt history, escrow refunds and the 200k callback budget. Update the site-facing ABI and docs for any changed calls.

Add adversarial tests for each finding and rerun the full Foundry suite, including listing/ad escrow. Clearly identify what still requires a real IMD Intake test.

Code only: no deployment, paid request or fund movement.