refactor(asr): 优化ASR助手的性能和资源管理

- 使用StringBuilder替代String拼接提升性能
- 清理ASR助手中的监听超时回调避免内存泄漏
- 在各个活动销毁时正确关闭图像解码执行器
- 修复语音识别中间结果的累积逻辑
- 优化ASR会话的资源释放流程

app/src/main/java/com/nova/brain/glass/helper/AsrHelper.kt

@@ -113,7 +113,7 @@ object AsrHelper : OfflineCmdListener {
     }
 
     // 拼接每次识别会话中的中间结果
-    private var currentPartial = ""
+    private val currentPartial = StringBuilder()
 
     /** 当前页面的场景标识，由各 Activity 在 onResume/onPause 中维护 */
     var scene: String = "home"
@@ -429,23 +429,20 @@ object AsrHelper : OfflineCmdListener {
             }
 
             override fun onStart(taskId: String) {
-                currentPartial = ""
+                currentPartial.clear()
                 restartListeningTimeout()
                 Log.d(TAG, "ASR started: $taskId")
             }
 
             override fun onPartialResult(taskId: String, text: String) {
-                // 滚动更新当前识别中间结果
-                currentPartial += text
+                currentPartial.append(text)
                 restartListeningTimeout()
                 Log.d(TAG, "ASR partial: $text")
             }
 
             override fun onFinalResult(taskId: String, text: String) {
-                // 将最终结果追加拼接到会话字符串
                 isMicRunning = false
-                // 滚动更新当前识别中间结果
-                currentPartial += text
+                currentPartial.append(text)
                 asr?.stopAsrWithMic()
                 Log.d(TAG, "ASR final result: $text")
                 dismissListeningDialog()
@@ -590,6 +587,7 @@ object AsrHelper : OfflineCmdListener {
     fun close() {
         isClosed = true
         OfflineCmdServiceHelper.removeOnLineListener(this)
+        mainHandler.removeCallbacks(listeningTimeoutRunnable)
         mainHandler.removeCallbacks(networkCheckRunnable)
         mainHandler.removeCallbacks(asrReconnectRunnable)
         mainHandler.removeCallbacks(ttsReconnectRunnable)

app/src/main/java/com/nova/brain/glass/ui/InspectionResultActivity.kt

@@ -232,6 +232,7 @@ class InspectionResultActivity :
     }
 
     override fun onDestroy() {
+        imageDecodeExecutor.shutdown()
         super.onDestroy()
         binding.iv.setImageDrawable(null)
         window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)

app/src/main/java/com/nova/brain/glass/ui/SprayingFinishActivity.kt

@@ -56,6 +56,7 @@ class SprayingFinishActivity :
     }
 
     override fun onDestroy() {
+        imageDecodeExecutor.shutdown()
         super.onDestroy()
         binding.photo1.setImageDrawable(null)
         binding.photo2.setImageDrawable(null)

app/src/main/java/com/nova/brain/glass/ui/SprayingOCRActivity.kt

@@ -152,6 +152,7 @@ class SprayingOCRActivity :
     }
 
     override fun onDestroy() {
+        imageDecodeExecutor.shutdown()
         viewModel.cancelUpload()
         super.onDestroy()
         binding.content.setImageDrawable(null)

app/src/main/java/com/nova/brain/glass/ui/SprayingResultActivity.kt

@@ -256,6 +256,7 @@ class SprayingResultActivity :
     }
 
     override fun onDestroy() {
+        imageDecodeExecutor.shutdown()
         uiHandler.removeCallbacksAndMessages(null)
         successDialog?.dismiss()
         super.onDestroy()