v0.55.3 — native Claude calls are booked at what they settle

Fixed — native Claude calls are booked at what they settle

blockrun_chat with thinking (the native /v1/messages path) books the
gateway's x402 quote, which prices output at a fraction of max_tokens and
settles it regardless of usage. The gateway raised that fraction from 0.1 to
0.5 on 2026-10-30, and this server kept booking 0.1, so a default opus call
was booked at about a quarter of what it paid and budget caps ran roughly 4x
loose on that path. It now books 0.5, re-verified against live quotes.

npm run verify:prices now probes /v1/messages too, and fails if the ledger
books below the live quote, so the next move of that fraction is caught.