fix: 缩小二维码白色边框（静默区 4格→1格）

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/xiaoqu/watch/ui/bind/BindFragment.kt

@@ -70,10 +70,13 @@ class BindFragment : BaseFragment<FragmentBindBinding>() {
             ))
             Timber.d("绑定: QR 数据=$qrData")
 
-            // ZXing 生成二维码 Bitmap
+            // ZXing 生成二维码 Bitmap（缩小静默区，让二维码更大）
             val size = 500
+            val hints = hashMapOf<com.google.zxing.EncodeHintType, Any>(
+                com.google.zxing.EncodeHintType.MARGIN to 1  // 默认4格，改为1格
+            )
             val bitMatrix: BitMatrix = MultiFormatWriter().encode(
-                qrData, BarcodeFormat.QR_CODE, size, size
+                qrData, BarcodeFormat.QR_CODE, size, size, hints
             )
             val bitmap = bitMatrixToBitmap(bitMatrix)
             binding.ivQrCode.setImageBitmap(bitmap)