feat: 优化发送验证码按钮，增加加载状态并调整倒计时逻辑

src/components/send-sms.vue

@@ -1,10 +1,25 @@
 <template>
-  <van-button type="primary" @click="triggerCountdown" :disabled="isCounting">
-    发送验证码
-    {{ !isCounting ? '' : `(${countdownTime}s)` }}
-  </van-button>
+  <Button
+    :label="`发送验证码${isCounting ? `(${countdownTime}s)` : ''}`"
+    variant="link"
+    @click="sendSms"
+    :loading="isSending"
+    :disabled="isSending || isCounting"
+  />
 </template>
 
 <script setup lang="ts">
-const { countdownTime, triggerCountdown, isCounting } = useCountdown(3);
+const { countdownTime, triggerCountdown, isCounting } = useCountdown($__DEV__ ? 5 : 60);
+
+const isSending = ref(false);
+const sendSms = async () => {
+  console.debug('[sendSms]');
+  isSending.value = true;
+  try {
+    await new Promise((resolve) => setTimeout(resolve, 1000));
+    triggerCountdown();
+  } finally {
+    isSending.value = false;
+  }
+};
 </script>