feat(FeedBack): 优化反馈界面交互和文本复制功能

更新反馈窗口的UI交互逻辑，包括：
- 调整按钮可见性状态
- 添加复制成功后的状态反馈文本
- 简化反馈链接卡片布局

Signed-off-by: doudou0720 <98651603+doudou0720@users.noreply.github.com>

Ink Canvas/Windows/FeedbackWindow.xaml

@@ -155,23 +155,7 @@
                             </Button.Style>
                         </Button>
                         <ui:SettingsExpander.Items>
-                            <ui:SettingsCard Header="复制反馈链接" IsClickEnabled="True" Click="CardCopyIssueUrl_Click">
-                                <TextBox x:Name="TextBoxIssueUrl"
-                                         MaxWidth="400"
-                                         Text="https://github.com/InkCanvasForClass/community/issues/new?template=01-bug_report.yml"
-                                         IsReadOnly="True"
-                                         BorderThickness="0"
-                                         Background="Transparent"
-                                         FontFamily="Consolas"
-                                         FontSize="12"
-                                         TextWrapping="Wrap"
-                                         AcceptsReturn="True"
-                                         HorizontalScrollBarVisibility="Auto"
-                                         VerticalScrollBarVisibility="Auto"
-                                         IsReadOnlyCaretVisible="False"
-                                         Foreground="{DynamicResource {x:Static ui:ThemeKeys.TextFillColorSecondaryBrushKey}}"
-                                         TextAlignment="Left"
-                                         VerticalAlignment="Center"/>
+                            <ui:SettingsCard x:Name="CardCopyIssueUrl" Header="复制反馈链接" IsClickEnabled="True" Click="CardCopyIssueUrl_Click">
                                 <ui:SettingsCard.ActionIcon>
                                     <ui:FontIcon Icon="{x:Static ui:SegoeFluentIcons.Copy}"/>
                                 </ui:SettingsCard.ActionIcon>

Ink Canvas/Windows/FeedbackWindow.xaml.cs

@@ -255,6 +255,8 @@ namespace Ink_Canvas
                 ButtonNext.Visibility = Visibility.Collapsed;
                 ButtonBack.Visibility = Visibility.Visible;
                 ButtonConfirm.Visibility = Visibility.Visible;
+                CardCopyIssueUrl.Header = "复制反馈链接";
+                BtnCopyMarkdown.Content = "复制模板";
             }
             else if (Page2.Visibility == Visibility.Visible)
             {
@@ -374,7 +376,7 @@ namespace Ink_Canvas
             GenerateMarkdownTemplate();
             Page2.Visibility = Visibility.Collapsed;
             Page3.Visibility = Visibility.Visible;
-            ButtonCancel.Visibility = Visibility.Visible;
+            ButtonCancel.Visibility = Visibility.Collapsed;
             ButtonNext.Visibility = Visibility.Collapsed;
             ButtonBack.Visibility = Visibility.Visible;
             ButtonConfirm.Visibility = Visibility.Collapsed;
@@ -622,6 +624,7 @@ namespace Ink_Canvas
                 }
 
                 Clipboard.SetText(url);
+                CardCopyIssueUrl.Header = "已复制 ✓";
             }
             catch (Exception ex)
             {
@@ -634,6 +637,7 @@ namespace Ink_Canvas
             try
             {
                 Clipboard.SetText(TextBoxMarkdownTemplate.Text);
+                BtnCopyMarkdown.Content = "已复制 ✓";
             }
             catch (Exception ex)
             {