Generate a compact plugin artifact with shared validator runtimes

Summary

The plugin currently contains 13 generated validate.mjs files. Several appear to repeatedly bundle the same GraphQL, UI-validation, and telemetry code.

Self-contained validators make sense for standalone skill installation, but the combined plugin could share those runtimes.

Proposal

Produce two build outputs:

1. Self-contained skills for standalone installation.
2. A compact plugin artifact with:
   • shared validator modules at the plugin root;
   • small per-skill wrapper scripts;
   • only skill-specific schemas and assets duplicated where necessary.

OpenAI's plugin format supports complete ZIP, Git subdirectory, and npm artifacts, so the compact plugin need not match the standalone-skill layout:

https://developers.openai.com/plugins/build/plugins#marketplace-metadata

use real files and wrappers rather than symlinks, since Codex plugin archives reject links.

Expected result

• Standalone skills remain self-contained.
• Plugin validators retain existing behavior.
• Shared runtime code is stored once.
• Installed and cached plugin size is substantially reduced.

Start by tracing how the 13 generated validate.mjs files are produced and how the current plugin artifact is packaged. Compare the standalone-skill layout with the proposed plugin-root shared runtimes and per-skill wrappers; done means standalone skills remain self-contained, plugin behavior is unchanged, archives contain real files rather than links, and shared code is stored once.