Add public WordPress fuzz runtime contract

[chubes4]

Summary

• Add the versioned public wp-codebox/wordpress-fuzz-runtime-contract/v1 descriptor for WordPress fuzz runtime capabilities.
• Expose the descriptor through TypeScript contracts/runtime descriptor, PHP facade, ability metadata, WP-CLI, and Node CLI.
• Document the HBEX consumer contract, explicit unsupported capabilities, reset modes, artifact expectations, and destructive-mode requirements.
• Accept flattened typed artifact DTOs with top-level path/digest fields to satisfy the existing public DTO contract.

Tests

• npm run build
• npm run test:public-api-contract
• npx tsx tests/public-fuzz-workload-cli.test.ts
• npm run test:wordpress-plugin-public-runtime-abilities
• npm run test:php-public-api-facade
• npm run test:php-cli-command
• npm run test:command-router
• git diff --check

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5, OpenCode
• Used for: Implementing the public descriptor contract, wiring public surfaces, updating docs, adding contract tests, and verifying the branch.