LegacyPrintf uses inferStdLogLevel() to infer log level from message
text. Any message containing the word "error" is classified as ERROR
level, causing the entire signature-retry recovery flow (which succeeds)
to produce spurious ERROR log entries.
Changes:
- Remove noisy [SignatureCheck] debug logs inside isThinkingBlockSignatureError
that were logging every detected signature check as ERROR
- Change retry-start log to WARN level via [warn] prefix
- Change retry-success log to INFO level by removing "error" from message
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
c64ed46d05