Add fourteen skills from Dimillian/Skills, integrate the merged Snowflake and WordPress updates into the maintainer sync, and refresh registry metadata, attributions, walkthrough notes, and the 8.9.0 release notes while keeping validation warnings within budget.
Consolidate the repository into clearer apps, tools, and layered docs areas so contributors can navigate and maintain it more reliably. Align validation, metadata sync, and CI around the same canonical workflow to reduce drift across local checks and GitHub Actions.
