fix(solana): a settle whose outcome the gateway does not know is waited out, never "no charge"

[VickyXAI]

Follow-up to #176, from its pre-merge review (Opus + Fable reviewer passes). #176 merged before this landed, so it ships separately. No version bump.

With #176 every finished video reaches the payment-signed path on its first paid poll. When that settle times out, sol.blockrun.ai answers 402 Payment settlement outcome unknown with Retry-After: 90 and holds the job's claim; other polls get settlement in progress on a concurrent poll. The helper ignored Retry-After, spent its 3 re-signs one poll interval apart (~15s into a 90s hold) and threw "no charge was made" while that payment could still land — the tool then booked nothing.

• Held answers (isSettleHeld, classified on this answer's body and reason, never the remembered reason) honour Retry-After, re-sign with a fresh blockhash and do not spend the re-sign budget; the deadline bounds them. A later header-less 402 (Payment verification failed) still takes the bounded re-sign path.
• Once a payment's outcome is open, every exit is a BilledJobError billing "unknown" — the deadline, a 500 poll answer, an unreadable challenge, a funding refusal of the fresh settle — so blockrun_video books the quote and says the job MAY have been charged.
• A completion 402 whose challenge cannot be read falls back to payment-signed polling instead of aborting the finished job.
• Music/image (settled at POST) never enter the held path; Base and the account rail are untouched.

Tests: 5 added in test/solana-poll-ownership.test.ts, each red against the pre-fix solana-402.ts. typecheck, build, CLI-load and brand checks pass; npm test 1419/1419.