feat(墨迹渐隐): 添加在笔工具菜单中隐藏墨迹渐隐控制开关的功能

添加新设置选项，允许用户在笔工具菜单中隐藏墨迹渐隐控制开关。该功能包括：
- 新增设置属性 HideInkFadeControlInPenMenu
- 在设置界面添加对应的开关控件
- 实现开关状态同步和可见性更新逻辑
- 更新主界面笔工具菜单中的控制面板可见性

终于不怕课间有人玩墨迹渐隐了！！！

Ink Canvas/Windows/SettingsViews/SettingsViews/CanvasAndInkPanel.xaml

@@ -249,6 +249,20 @@
                             <TextBlock x:Name="InkFadeTimeText" Text="3000ms" VerticalAlignment="Center" FontSize="14" Margin="12,0,0,0" Foreground="#2e3436"/>
                         </StackPanel>
                     </Grid>
+                    <Border Height="1" Background="#ebebeb"/>
+                    <Grid Height="54">
+                        <StackPanel Orientation="Vertical" Margin="18,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Left">
+                            <TextBlock Foreground="#2e3436" FontSize="14.5" Text="在笔工具菜单中隐藏墨迹渐隐控制" HorizontalAlignment="Left"/>
+                            <TextBlock Foreground="#9a9996" FontSize="11" Margin="0,3.5,0,0" Text="开启后，主工具栏上点击笔工具后弹出的上下文菜单中将不显示墨迹渐隐控制开关" HorizontalAlignment="Left"/>
+                        </StackPanel>
+                        <Border x:Name="ToggleSwitchHideInkFadeControlInPenMenu" Style="{StaticResource ToggleSwitchStyle}" Background="#e1e1e1" Tag="HideInkFadeControlInPenMenu" MouseLeftButtonDown="ToggleSwitch_Click">
+                            <Border Width="19" Height="19" Background="White" CornerRadius="10" HorizontalAlignment="Left" VerticalAlignment="Center">
+                                <Border.Effect>
+                                    <DropShadowEffect BlurRadius="4" Direction="-45" Color="Black" Opacity="0.3" ShadowDepth="0"/>
+                                </Border.Effect>
+                            </Border>
+                        </Border>
+                    </Grid>
                 </StackPanel>
             </Border>
             

Ink Canvas/Windows/SettingsViews/SettingsViews/CanvasAndInkPanel.xaml.cs

@@ -360,6 +360,11 @@ namespace Ink_Canvas.Windows.SettingsViews
                     }
                     break;
 
+                case "HideInkFadeControlInPenMenu":
+                    // 调用 MainWindow 中的方法
+                    MainWindowSettingsHelper.InvokeToggleSwitchToggled("ToggleSwitchHideInkFadeControlInPenMenu", newState);
+                    break;
+
                 case "EnableAutoSaveStrokes":
                     // 调用 MainWindow 中的方法
                     MainWindowSettingsHelper.InvokeToggleSwitchToggled("ToggleSwitchEnableAutoSaveStrokes", newState);