修复打印机查纸状态无前端反馈问题

app/src/main/java/com/stand/standapp/printer/PrinterManager.kt

@@ -27,8 +27,13 @@ object PrinterManager {
             mContext?.let {
                 if (!hasPaper) {
                     android.widget.Toast.makeText(it, "⚠️ 警告：打印机缺纸！", android.widget.Toast.LENGTH_LONG).show()
+                } else {
+                    android.widget.Toast.makeText(it, "打印机状态：正常 (有纸)", android.widget.Toast.LENGTH_SHORT).show()
                 }
             }
+            
+            // 通知前端页面
+            com.stand.standapp.MainActivity.executeJs("if(window.onPaperStateChanged) { window.onPaperStateChanged($hasPaper); }")
         }
         true
     }