feat: implement user and admin login flow

server/api/login/user.post.ts

@@ -0,0 +1,22 @@
+import { defineEventHandler, readBody, setResponseStatus } from 'h3';
+
+export default defineEventHandler(async (event) => {
+  const body = await readBody(event);
+  const { contact, password } = body;
+
+  if (!contact || !password) {
+    setResponseStatus(event, 400);
+    return { message: '请填写手机号和密码' };
+  }
+
+  // TODO: Replace with database user lookup and password verification
+  if (contact === '1234567890' && password === 'password') {
+    return {
+      message: '登录成功！',
+      customerId: 'dummy-customer-id-123',
+    };
+  } else {
+    setResponseStatus(event, 401);
+    return { message: '手机号或密码错误' };
+  }
+});