Delegate WordPress execution to WP Codebox

[chubes4]

Summary

• project WordPress Core through canonical wordpress_directory instead of plugin mounts
• replace the legacy 1,500-line PHPUnit and bench runners with thin WP Codebox CLI adapters
• remove browser recipe orchestration, compatibility discovery, local recipe builders, and stale aliases
• standardize public plugin inputs on extra_plugins, wp_codebox_source_root, and wp_codebox_source_subpath

Why

The WordPress extension independently rebuilt WP Codebox source resolution, recipe construction, PHPUnit discovery, dependency handling, browser orchestration, and artifact parsing. That duplicated the runtime owner and allowed the two contracts to drift.

This change leaves Homeboy Extensions responsible for Homeboy request/result projection while WP Codebox owns runtime construction and execution.

Upstream dependency: Automattic/wp-codebox#1865

How to test

1. Run cd wordpress from a fresh checkout.
2. Run node tests/wp-codebox-canonical-cli-adapters-smoke.mjs.
3. Run node tests/codebox-client-boundary.test.js.
4. Run node tests/wordpress-fuzz-runner-smoke.js.
5. Run node tests/wp-codebox-fuzz-run-smoke.js.
6. Run npm pack --dry-run --ignore-scripts.

Compatibility

This deliberately removes legacy Codebox settings, camelCase request aliases, sibling-worktree/cache/global-module discovery, and the legacy artifact preflight path. Existing callers must use the canonical installed runtime binary and canonical snake_case input contract. No backwards-compatibility shim is retained.

AI assistance

• AI assistance: Yes
• Tool(s): OpenAI gpt-5.6-sol via OpenCode
• Used for: Cross-repository contract analysis, implementation, test migration, and PR preparation under Chris Huber's direction.