chore: remove unused dependencies (radix-ui, class-variance-authority)

Remove 5 unused production dependencies:
- @radix-ui/react-collapsible
- @radix-ui/react-scroll-area
- @radix-ui/react-separator
- @radix-ui/react-tooltip
- class-variance-authority

These were leftover from initial scaffolding and never imported.
Reduces install footprint and dependency count.

package.json

@@ -37,12 +37,7 @@
     "lint:fix": "eslint . --fix"
   },
   "dependencies": {
-    "@radix-ui/react-collapsible": "^1.1.12",
-    "@radix-ui/react-scroll-area": "^1.2.10",
-    "@radix-ui/react-separator": "^1.1.8",
-    "@radix-ui/react-tooltip": "^1.2.8",
     "@tailwindcss/vite": "^4.1.18",
-    "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^0.563.0",
     "react": "^19.2.0",