refactor: 移除java项目，改用hono + vercel function实现后端 (#1)

Co-authored-by: gin <gin-18@qq.com>
Co-authored-by: gin <dengxinmin@owlscm.com>
Reviewed-on: #1

frontend/README.md

@@ -0,0 +1,63 @@
+# Frontend
+
+Frontend packages are managed by the root pnpm workspace.
+
+This directory contains:
+
+- `web`: Vite + Vue 3 admin frontend.
+- `app`: Taro + Vue 3 app frontend.
+
+Run commands from the repository root:
+
+```bash
+pnpm install
+pnpm dev:web
+pnpm dev:app:weapp
+```
+
+## Environment Files
+
+Frontend environment variables are maintained in each app directory.
+
+### Web
+
+Web env files live in `frontend/web`:
+
+- `.env`: default Vite values.
+- `.env.development`: local development values.
+- `.env.production`: production build values.
+- `.env.staging`: staging build values.
+
+Common variables:
+
+```env
+VITE_PORT=8848
+VITE_PUBLIC_PATH=./
+VITE_ROUTER_HISTORY="hash"
+VITE_CDN=false
+VITE_COMPRESSION="none"
+VITE_APP_BASE_API=/dev-api
+```
+
+For Vercel deployment, create a Web project with `frontend/web` as the Root
+Directory. Use the Vite framework preset, `pnpm install`, `pnpm build`, and
+`dist` as the output directory. Configure `VITE_APP_BASE_API` in Vercel with
+the deployed backend URL.
+
+### App
+
+App env files live in `frontend/app`:
+
+- `.env.development`: local development values.
+- `.env.production`: production build values.
+- `.env.test`: test build values.
+
+Common variables:
+
+```env
+TARO_APP_ID=
+TARO_APP_API_BASE=
+```
+
+When `TARO_APP_API_BASE` is empty, the app HTTP client falls back to
+`http://localhost:3000`.