fix: use Vite API directly for global CLI

Spawn-based approach fails on global install because node_modules
is hoisted. Use programmatic Vite API instead. Move vite, plugin-vue,
and sass to dependencies so they're available at runtime.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -24,21 +24,21 @@
     "package.json"
   ],
   "dependencies": {
+    "@vitejs/plugin-vue": "^6.0.5",
     "highlight.js": "^11.11.1",
     "markdown-it": "^14.1.1",
     "naive-ui": "^2.44.1",
     "pinia": "^3.0.4",
+    "sass": "^1.99.0",
+    "vite": "^8.0.4",
     "vue": "^3.5.32",
     "vue-router": "^4.6.4"
   },
   "devDependencies": {
     "@types/markdown-it": "^14.1.2",
     "@types/node": "^24.12.2",
-    "@vitejs/plugin-vue": "^6.0.5",
     "@vue/tsconfig": "^0.9.1",
-    "sass": "^1.99.0",
     "typescript": "~6.0.2",
-    "vite": "^8.0.4",
     "vue-tsc": "^3.2.6"
   }
 }