fix: index page layout — separate badge from reconnect, space buttons

- Device card: top row with icon+name+badge, reconnect button below
- Action buttons wrapped in flex column with 20rpx gap
- Removed inline device-battery, now part of device-meta row

miniprogram/pages/index/index.wxss

@@ -19,6 +19,69 @@
   border: none;
 }
 
+.device-card {
+  background: #fff;
+  border-radius: 16rpx;
+  padding: 28rpx;
+}
+
+.device-card-top {
+  display: flex;
+  align-items: center;
+  gap: 20rpx;
+}
+
+.device-icon {
+  font-size: 64rpx;
+  flex-shrink: 0;
+}
+
+.device-info {
+  flex: 1;
+}
+
+.device-name {
+  font-size: 32rpx;
+  font-weight: 600;
+  color: #333;
+  margin-bottom: 8rpx;
+}
+
+.device-meta {
+  display: flex;
+  align-items: center;
+  gap: 16rpx;
+}
+
+.device-battery-text {
+  font-size: 24rpx;
+  color: #666;
+}
+
+.btn-reconnect {
+  display: block;
+  width: 100%;
+  margin-top: 20rpx;
+  padding: 20rpx;
+  background: #f5f5f5;
+  color: #E6508C;
+  border: 2rpx solid #E6508C;
+  border-radius: 12rpx;
+  font-size: 28rpx;
+  text-align: center;
+}
+
+.btn-reconnect::after {
+  border: none;
+}
+
+.action-buttons {
+  margin-top: 30rpx;
+  display: flex;
+  flex-direction: column;
+  gap: 20rpx;
+}
+
 .sub-info {
   display: flex;
   justify-content: space-between;