The skills-index page had drifted badly (claimed 66 skills; 330 are actually
installed). Regenerate it from the live skill tree and add an automated
regeneration script + related cron so it can never go stale again.
- regenerate-skills-index.sh: full stock-take (inventory -> quartz build -> deploy)
- systems/skills-index.md: rebuilt with all 330 skills across 26 categories
- .gitignore: fix stray literal chars, ignore build artifacts
Tony0410