feat: add Nuxt UI stack support (#35)

- Add nuxt-ui.csv with 50 guidelines covering installation, components,
    forms, theming, dashboard, tables, navigation, and more
  - Register nuxt-ui in STACK_CONFIG (core.py)
  - Update README.md to reflect 9 tech stacks

.claude/skills/ui-ux-pro-max/scripts/core.py

@@ -62,6 +62,7 @@ STACK_CONFIG = {
     "react": {"file": "stacks/react.csv"},
     "nextjs": {"file": "stacks/nextjs.csv"},
     "vue": {"file": "stacks/vue.csv"},
+    "nuxt-ui": {"file": "stacks/nuxt-ui.csv"},
     "svelte": {"file": "stacks/svelte.csv"},
     "swiftui": {"file": "stacks/swiftui.csv"},
     "react-native": {"file": "stacks/react-native.csv"},