fix: 返回按钮改为整个标题栏左半边可点击

去掉 TouchDelegate，改用 FrameLayout 占标题栏左半边(weight=1)
图标靠左显示，但整个左半边 48dp 高的区域都能触发返回

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

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

@@ -87,19 +87,10 @@ class TaskListFragment : BaseFragment<FragmentTaskListBinding>() {
         val dialogContainer = requireActivity().findViewById<FrameLayout>(R.id.dialog_container)
         tipDialog = QuTipDialog(dialogContainer)
 
-        // 返回按钮（扩大触摸区域，图标大小不变）
+        // 返回按钮（整个左半边都可点击）
         binding.btnBack.setOnClickListener {
             findNavController().popBackStack()
         }
-        // 用 TouchDelegate 向下和向右扩展点击区域
-        binding.btnBack.post {
-            val parent = binding.btnBack.parent as View
-            val rect = android.graphics.Rect()
-            binding.btnBack.getHitRect(rect)
-            rect.bottom += (20 * resources.displayMetrics.density).toInt()
-            rect.right += (40 * resources.displayMetrics.density).toInt()
-            parent.touchDelegate = android.view.TouchDelegate(rect, binding.btnBack)
-        }
 
         // 左右滑手势（切换任务），上下滑留给内容滚动
         gestureDetector = GestureDetector(requireContext(), object : GestureDetector.SimpleOnGestureListener() {

app/src/main/res/layout/fragment_task_list.xml

@@ -19,16 +19,25 @@
         android:paddingEnd="21dp"
         android:paddingBottom="4dp">
 
-        <!-- 返回按钮：iconfont 图标，点击区域由 TouchDelegate 扩展 -->
+        <!-- 返回按钮：整个左半边可点击，图标靠左 -->
-        <TextView
+        <FrameLayout
             android:id="@+id/btnBack"
-            android:layout_width="64dp"
+            android:layout_width="0dp"
-            android:layout_height="match_parent"
+            android:layout_height="48dp"
-            android:gravity="center"
+            android:layout_weight="1"
+            android:clickable="true"
+            android:focusable="true">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center_vertical"
+                android:paddingStart="21dp"
                 android:text="\ue6bd"
                 android:fontFamily="@font/iconfont"
                 android:textColor="@color/text_primary"
                 android:textSize="28sp" />
+        </FrameLayout>
 
         <TextView
             android:id="@+id/tvTitle"