chore: remove boilerplate demo content, fix components.json

Drop the unrecognized `framework` key from components.json (current
shadcn-vue CLI rejects it). Delete the counter store demo and reduce
HomeView to a placeholder; real content lands in a later commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components.json

@@ -9,7 +9,6 @@
     "cssVariables": true,
     "prefix": ""
   },
-  "framework": "vite",
   "aliases": {
     "components": "@/components",
     "composables": "@/composables",