Emit DB write-set fuzz artifacts

[chubes4]

Summary

• Add the public wp-codebox/wordpress-db-write-set/v1 contract and exports for destructive fuzz DB write ledgers.
• Capture generic SQL write sets from REST/admin query capture plus CRUD/DB destructive runtime actions.
• Persist per-case write-set artifacts in fuzz bundles and expose inline case metadata for non-durable runs.

Tests

• npm run build
• npm run test:playground-fuzz-suite-public
• npm run test:fuzz-suite-runner

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 via OpenCode
• Used for: Implementing the DB write-set contract, runtime artifact emission, tests, and docs.