feat: migrate skills to collection, replace with resources page

Move internal skills out of public blog collection into .claude
submodule. Add ResourceCard component and resources.ts data model.
Create /resources page showcasing MuleFlow, DataWeave, AccessibilityReview,
and other tools. Update icon set and refactor skill-related routes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: alexandramartinez