fix: add path alias configuration in vite.config.js

- Fix 'Failed to resolve import @/stores/function' error
- Add '@' alias pointing to './src' directory
- Enable cleaner import paths in Vue components

Before:
  import { useFunctionStore } from '@/stores/function'  // Error!

After:
  import { useFunctionStore } from '@/stores/function'  // Works!

Changes:
- Import 'path' module
- Configure resolve.alias in vite.config.js
- Add fix documentation

frontend/vite.config.js

@@ -1,9 +1,15 @@
 import { defineConfig } from 'vite'
 import vue from '@vitejs/plugin-vue'
+import path from 'path'
 
 // https://vitejs.dev/config/
 export default defineConfig({
   plugins: [vue()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src')
+    }
+  },
   server: {
     host: '0.0.0.0',  // 允许局域网访问
     port: 5173,