Phase 1: versioning, menu bar, About dialog, right-click context menu

- Directory.Build.props sets Version=0.1.0 (semver pre-1.0 = beta) plus
  Authors / Product / RepositoryUrl, picked up by all three projects.
- MainWindow gets a real menu bar (File / Server / Help) replacing the
  old toolbar. File: New endpoint / Import / Export / Backups (last
  three are stubs for the next phase) / Exit. Server: Settings /
  Restart service. Help: About.
- Drop the Refresh button - the 3 s polling loop covers it.
- DataGridRow gets a right-click context menu: Edit / Copy URL /
  toggle Enabled / Delete.
- New About dialog reads AssemblyInformationalVersion at runtime and
  links jpaul.me + the GitHub repo via clickable hyperlinks.
- Ctrl+N input binding for new-endpoint.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/WebhookServer.Gui/Views/AboutDialog.xaml

@@ -0,0 +1,42 @@
+<Window x:Class="WebhookServer.Gui.Views.AboutDialog"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="About Webhook Server"
+        Height="320" Width="420"
+        ResizeMode="NoResize"
+        WindowStartupLocation="CenterOwner"
+        ShowInTaskbar="False">
+    <Grid Margin="20">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="*"/>
+            <RowDefinition Height="Auto"/>
+        </Grid.RowDefinitions>
+
+        <TextBlock Grid.Row="0" Text="Webhook Server" FontSize="22" FontWeight="Bold"/>
+        <TextBlock Grid.Row="1" x:Name="VersionText" Foreground="Gray" Margin="0,4,0,16"/>
+
+        <TextBlock Grid.Row="2" TextWrapping="Wrap">
+            A Windows-native webhook server that runs PowerShell, cmd, or arbitrary
+            executables in response to incoming HTTP requests.
+        </TextBlock>
+
+        <StackPanel Grid.Row="3" Margin="0,16,0,0">
+            <TextBlock>
+                <Run Text="Created by"/>
+                <Run Text="Justin Paul" FontWeight="SemiBold"/>
+            </TextBlock>
+            <TextBlock Margin="0,4,0,0">
+                <Hyperlink NavigateUri="https://jpaul.me" RequestNavigate="OnHyperlink">https://jpaul.me</Hyperlink>
+            </TextBlock>
+            <TextBlock Margin="0,4,0,0">
+                <Hyperlink NavigateUri="https://github.com/recklessop/webhook-server" RequestNavigate="OnHyperlink">github.com/recklessop/webhook-server</Hyperlink>
+            </TextBlock>
+        </StackPanel>
+
+        <Button Grid.Row="5" Content="OK" Width="80" HorizontalAlignment="Right" IsDefault="True" IsCancel="True" Click="OnOk"/>
+    </Grid>
+</Window>