Add query observation fuzz artifacts

[chubes4]

Summary

• Add public wp-codebox/query-observation/v1 contract/types and expose it through public/contract barrels and the runtime contract manifest.
• Materialize per-fuzz-case query observation JSON artifacts in durable fuzz bundles, with inline metadata when artifact storage is not enabled.
• Extend the shared query recorder with operation/table metadata and document the contract.

Tests

• npm run test:playground-fuzz-suite-public
• npm run test:runtime-contract-manifest
• npm run test:public-api-contract
• npm run build

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 via OpenCode
• Used for: Drafted and implemented the query observation contract, runtime artifact extraction, tests, and documentation.