fix: 代码遗漏修复（NFC回调安全+绑定电量+信号初始值）

1. NFC 打卡回调加 isAdded/view 安全检查，防止 Fragment 销毁后崩溃
2. postDelayed 回调同样加保护
3. 绑定二维码电量从写死100改为读取实时电量
4. 信号强度启动时主动读一次初始值（和蓝牙同样处理）

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

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

@@ -60,13 +60,23 @@ class BindFragment : BaseFragment<FragmentBindBinding>() {
      * 编码设备信息 JSON：{bluetoothName, imei, serial, power}
      * 与旧版 codeScanPair.vue 格式一致
      */
+    /** 获取当前电量百分比 */
+    private fun getCurrentBatteryLevel(): Int {
+        val intent = requireContext().registerReceiver(
+            null, android.content.IntentFilter(android.content.Intent.ACTION_BATTERY_CHANGED)
+        ) ?: return 100
+        val level = intent.getIntExtra(android.os.BatteryManager.EXTRA_LEVEL, 0)
+        val scale = intent.getIntExtra(android.os.BatteryManager.EXTRA_SCALE, 100)
+        return (level * 100) / scale
+    }
+
     private fun generateQrCode() {
         try {
             val qrData = gson.toJson(mapOf(
                 "bluetoothName" to devicePrefs.bluetoothName,
                 "imei" to devicePrefs.imei,
                 "serial" to devicePrefs.serial,
-                "power" to 100  // TODO: 接入实时电量
+                "power" to getCurrentBatteryLevel()
             ))
             Timber.d("绑定: QR 数据=$qrData")
 

app/src/main/java/com/xiaoqu/watch/ui/home/HomeFragment.kt

@@ -328,6 +328,17 @@ class HomeFragment : BaseFragment<FragmentHomeBinding>() {
         val btAdapter = android.bluetooth.BluetoothAdapter.getDefaultAdapter()
         val btOn = btAdapter?.isEnabled ?: false
         statusBar.updateBluetooth(btOn)
+
+        // 信号强度初始值（PhoneStateListener 注册后才有回调，先读一次当前值）
+        try {
+            val telephony = requireContext().getSystemService(android.content.Context.TELEPHONY_SERVICE)
+                as? android.telephony.TelephonyManager
+            val signalLevel = telephony?.signalStrength?.level ?: 0
+            statusBar.updateSignal(signalLevel)
+        } catch (e: Exception) {
+            // signalStrength 可能为 null（API 28+），静默处理
+            statusBar.updateSignal(0)
+        }
     }
 
     /** 初始化主页数据 */

app/src/main/java/com/xiaoqu/watch/ui/task/TaskListFragment.kt

@@ -820,7 +820,9 @@ class TaskListFragment : BaseFragment<FragmentTaskListBinding>() {
         btn.setBackgroundResource(R.drawable.bg_foot_btn_grey)
 
         nfcTaskManager.startTaskPunch(taskId) { success, message ->
-            // 恢复按钮可点击状态
+            // NFC 回调可能在 Fragment 销毁后触发，需要安全检查
+            if (!isAdded || view == null) return@startTaskPunch
+
             btn.isEnabled = true
             if (success) {
                 tipDialog.show(
@@ -828,7 +830,9 @@ class TaskListFragment : BaseFragment<FragmentTaskListBinding>() {
                     title = "打卡成功"
                 )
                 // 2 秒后（弹窗消失后）刷新任务详情
-                btn.postDelayed({ fetchCurrentDetail() }, 2100)
+                btn.postDelayed({
+                    if (isAdded && view != null) fetchCurrentDetail()
+                }, 2100)
             } else {
                 if (message != "超时") {
                     tipDialog.show(