style: 备注样式优化

- 加"备注"标签（18sp 灰色），用户知道这块文字是什么
- 内容改白色文字（text_primary），对比度更高
- 背景从绿色改为深灰卡片色+细边框，和指引块（橙/绿）区分
- 新建 bg_note.xml 替换 bg_note_green.xml

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

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

@@ -258,7 +258,7 @@ class TaskListFragment : BaseFragment<FragmentTaskListBinding>() {
         binding.tvPoints.visibility = View.GONE
         binding.picScrollView.visibility = View.GONE
         binding.picContainer.removeAllViews()
-        binding.tvNote.visibility = View.GONE
+        binding.noteContainer.visibility = View.GONE
         binding.btnVoice.visibility = View.GONE
         binding.blockGoWhere.visibility = View.GONE
         binding.blockNoScene.visibility = View.GONE
@@ -378,7 +378,7 @@ class TaskListFragment : BaseFragment<FragmentTaskListBinding>() {
         }
         if (note != null) {
             binding.tvNote.text = note
-            binding.tvNote.visibility = View.VISIBLE
+            binding.noteContainer.visibility = View.VISIBLE
         }
     }