Modularize WordPress plugin abilities

[chubes4]

Summary

• Split the WordPress plugin abilities monolith into focused internal traits for schemas, execution, permissions, inheritance, browser artifacts, browser runtime, browser blueprint, browser runner, and utilities.
• Kept the WP_Codebox_Abilities public class and callback surface intact so existing ability and WP-CLI callers continue to resolve the same methods.
• Preserved behavior with a mechanical decomposition and verified the refactored method set matches the original branch implementation.

Verification

• php -l across class-wp-codebox-abilities.php and all trait-wp-codebox-abilities-*.php files
• npm run wordpress-plugin-smoke (OK (346 assertions))
• git diff --check
• Method-set comparison against HEAD before the split (137 methods preserved)

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Mechanical decomposition of the PHP abilities monolith into focused traits, plus targeted syntax/smoke verification. Chris remains responsible for review and merge decisions.