Stop retrying terminal provider billing errors

[mrubens]

Summary

• classify provider billing, suspension, and payment-required responses as terminal
• stop OpenCode retry backoff when a retry status contains a terminal provider error
• surface the provider message, clear queued prompts, and abort the task
• preserve existing retry behavior for transient provider failures

Validation

• focused OpenCode harness tests
• worker typecheck
• worker lint
• formatting checks
• pre-push checks (oxlint, residual lint, check-types:fast, knip)

[roomote-roomote]

1 issue outstanding. See task

• apps/worker/src/sandbox-server/lib/harnesses/opencode-server/provider-error-recovery.ts:153 handleSessionStatus calls this classifier with only { message }, so the 402/payment_required fields covered by the new test are unavailable. A retry status whose message is simply Payment required is not matched by the string checks and therefore stays in OpenCode's retry loop, contrary to the stated payment-required behavior. Match that message-only form (and add a retry-status regression test).

_{Reviewed e66982f}