Update splash screen svg and translation

src/UniGetUI.Avalonia/Views/SplashWindow.axaml

@@ -14,11 +14,30 @@
             BorderBrush="{DynamicResource AppBorderBrush}"
             BorderThickness="1"
             BoxShadow="0 8 32 0 #40000000"
-            Margin="16">
-        <Image x:Name="SplashImage"
-               Stretch="Uniform"
-               HorizontalAlignment="Center"
-               VerticalAlignment="Center"
-               Margin="24"/>
+            Margin="16"
+            ClipToBounds="True">
+        <!-- Column/row ratios match the wordmark bounding box (x 245-480, y 78-193) in the 620x300 SVG viewBox, so the tagline cell sits directly below the wordmark. -->
+        <Grid>
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="245*"/>
+                <ColumnDefinition Width="235*"/>
+                <ColumnDefinition Width="140*"/>
+            </Grid.ColumnDefinitions>
+            <Grid.RowDefinitions>
+                <RowDefinition Height="200*"/>
+                <RowDefinition Height="100*"/>
+            </Grid.RowDefinitions>
+            <Image x:Name="SplashImage"
+                   Grid.ColumnSpan="3"
+                   Grid.RowSpan="2"
+                   Stretch="Uniform"/>
+            <TextBlock x:Name="TaglineText"
+                       Grid.Column="1"
+                       Grid.Row="1"
+                       HorizontalAlignment="Center"
+                       VerticalAlignment="Top"
+                       Margin="0,8,0,0"
+                       FontSize="15"/>
+        </Grid>
     </Border>
 </Window>

src/UniGetUI.Avalonia/Views/SplashWindow.axaml.cs

@@ -1,9 +1,11 @@
 using System;
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Media;
 using Avalonia.Media.Imaging;
 using Avalonia.Platform;
 using Avalonia.Styling;
+using UniGetUI.Core.Tools;
 
 namespace UniGetUI.Avalonia.Views;
 
@@ -18,5 +20,8 @@ public SplashWindow()
             ? "avares://UniGetUI.Avalonia/Assets/SplashScreen.theme-dark.png"
             : "avares://UniGetUI.Avalonia/Assets/SplashScreen.png";
         SplashImage.Source = new Bitmap(AssetLoader.Open(new Uri(uri)));
+
+        TaglineText.Text = CoreTools.Translate("Package management made easy");
+        TaglineText.Foreground = isDark ? Brushes.White : Brushes.Black;
     }
 }