replace .env.development[production].local with .env.development[production];add env example

frontend/.env_development_example

@@ -0,0 +1 @@
+NEXT_PUBLIC_API_URL=http://43.142.81.156:3001

frontend/.env_production_example

@@ -0,0 +1,5 @@
+NEXT_PUBLIC_API_URL=https://www.privydrop.app
+
+NEXT_PUBLIC_TURN_HOST=turn.privydrop.app
+NEXT_PUBLIC_TURN_USERNAME=[Username]
+NEXT_PUBLIC_TURN_PASSWORD=[Password]

frontend/README.md

@@ -25,7 +25,7 @@ Before you start, please ensure you have **installed and started the backend ser
     pnpm install
     ```
 3.  **Configure Environment Variables**
-    Create a `.env.development.local` file in the `frontend/` directory and add the necessary environment variables for development. At a minimum, you need to specify the backend API address:
+    Create a `.env.development` file in the `frontend/` directory and add the necessary environment variables for development. At a minimum, you need to specify the backend API address:
     ```ini
     NEXT_PUBLIC_API_URL=http://localhost:3001
     ```

frontend/README.zh-CN.md

@@ -25,7 +25,7 @@
     pnpm install
     ```
 3.  **配置环境变量**
-    在 `frontend/` 目录下创建 `.env.development.local` 文件，并填入开发所需的环境变量，至少需要指定后端 API 的地址：
+    在 `frontend/` 目录下创建 `.env.development` 文件，并填入开发所需的环境变量，至少需要指定后端 API 的地址：
     ```ini
     NEXT_PUBLIC_API_URL=http://localhost:3001
     ```