Wave 0 contracts for the verification engine are in place:
- VerifySpec extended with SuccessCodes/FailureCodes/RateLimitCodes/MetadataPaths/Body
- Finding extended with Verified/VerifyStatus/VerifyHTTPCode/VerifyMetadata/VerifyError
- findings table schema migrated with verify_* columns (fresh + legacy DBs)
- gjson dep wired as direct require
- VRFY-02, VRFY-03 marked complete
