Boot recipe active plugins before workflow

[chubes4]

Summary

• Declares active recipe extraPlugins through an early Playground setSiteOptions blueprint step so workflow commands boot WordPress with normal active-plugin loading.
• Removes the recipe setup late-activation step and keeps wordpress.bench hook replay only for true fallback activations.
• Expands the bench fixture regression to assert REST route visibility plus plugin inclusion before plugins_loaded and init fired.

Closes #419.

Tests

• npm run build
• npm run recipe-dry-run-smoke
• npm run recipe-bench-smoke
• npm run recipe-site-seed-smoke

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Implemented the boot-time active-plugin recipe/runtime path, updated focused regression coverage, and ran the focused verification commands. Chris remains responsible for review and merge.