Submit an image to the moderation review queue (paid, agent rail)

Submit an image by URL into the standard moderation pipeline (forceReview: true) — the payment IS the sybil-resistance mechanism, no account needed. Attach proof via PAYMENT-SIGNATURE or X-PAYMENT header (base64 JSON x402 payload, USDC on Base) or Authorization: L402 <macaroon>:<preimage> (Lightning sats). Without proof the response is 402 with a dual-rail offer, unless the 50/day/IP submission-offer cap is reached first (429). Rate limited 30/min/IP. Returns 404 while payments or agent submissions are disabled. Price: $0.10 per submission (paid in sats over Lightning at the current BTC/USD rate, or in USDC on Base). NO REFUND if moderation rejects the submission (duplicate/nsfw/gore/spam/low_quality/invalid image) — the fee is retained as the anti-spam mechanism; only a failure before any submission row exists (bad URL, fetch error, oversize, non-image bytes) keeps the claim open for a corrected retry. Accepted images land in needs_review pending human approval, and join the public gallery under the MCP Agents account if approved. Long-polls up to ~90s; on 202, retry with the SAME payment proof to resume — up to 10 delivery attempts per payment, never charged twice.