feat: rebrand to MMD PDF, single corporate theme, and remove original text under an edit

- Services/PdfRedactText.cs: strip text whose origin falls inside a CoverAnnotation
  from the page content stream at save time, hooked into PdfBurn.DrawAnnotationsIntoDoc.
  Fixes edited values staying recoverable by text extraction.
- Themes/MMD.xaml replaces all thirteen themes; picker and accent strip removed; no dark mode.
- Rename KillerPDF -> MMD PDF across code, resources, packaging and locale strings; new icon.
- Remove the upstream author credit and the in-app install button.

Controls/KillerDialog.cs

@@ -10,9 +10,9 @@ using System.Windows.Media;
 using System.Windows.Media.Animation;
 using System.Windows.Media.Imaging;
 using System.Windows.Shapes;
-using KillerPDF.Services;
+using MmdPdf.Services;
 
-namespace KillerPDF
+namespace MmdPdf
 {
     // ============================================================
     // Themed dialog - replaces MessageBox for dark-UI consistency
@@ -34,7 +34,7 @@ namespace KillerPDF
         public static MessageBoxResult Show(
             Window? owner,
             string message,
-            string title = "KillerPDF",
+            string title = "MmdPdf",
             MessageBoxButton buttons = MessageBoxButton.OK,
             MessageBoxImage image = MessageBoxImage.None,
             bool fadeClose = true,
@@ -76,9 +76,9 @@ namespace KillerPDF
                 CornerRadius = new CornerRadius(5, 5, 0, 0)
             };
             titleBar.MouseLeftButtonDown += (_, e) => { if (e.ButtonState == MouseButtonState.Pressed) win.DragMove(); };
-            // When the title is just "KillerPDF", render it as the main window's wordmark - "Killer"
+            // When the title is just "MmdPdf", render it as the main window's wordmark - "Killer"
             // in the primary text color and "PDF" in the green logo accent, bold, with a soft shadow.
-            if (title == "KillerPDF")
+            if (title == "MmdPdf")
             {
                 var wm = new StackPanel { Orientation = Orientation.Horizontal };
                 var wmTb = new TextBlock { VerticalAlignment = VerticalAlignment.Center };
@@ -216,7 +216,7 @@ namespace KillerPDF
             string message,
             string[] labels,
             int accentIndex = 0,
-            string title = "KillerPDF")
+            string title = "MmdPdf")
         {
             int result = -1;
 
@@ -238,7 +238,7 @@ namespace KillerPDF
 
             var titleBar = new Border { Background = Application.Current.TryFindResource("UseDialogCaption") is true ? UiKit.Brush("TitleBarBrush") : Brushes.Transparent, Padding = new Thickness(16, 10, 16, 10) };
             titleBar.MouseLeftButtonDown += (_, e) => { if (e.ButtonState == MouseButtonState.Pressed) win.DragMove(); };
-            if (title == "KillerPDF")
+            if (title == "MmdPdf")
             {
                 var wmTb = new TextBlock { VerticalAlignment = VerticalAlignment.Center };
                 wmTb.Inlines.Add(new System.Windows.Documents.Run("Killer") { FontFamily = UiKit.WordmarkFont, FontWeight = FontWeights.Normal, FontSize = 15, Foreground = R("TextBrush") });
@@ -308,7 +308,7 @@ namespace KillerPDF
             Window? owner,
             string message,
             string checkboxText,
-            string title = "KillerPDF",
+            string title = "MmdPdf",
             MessageBoxButton buttons = MessageBoxButton.OKCancel,
             MessageBoxResult? defaultResult = null)
         {
@@ -358,7 +358,7 @@ namespace KillerPDF
             bool closeTabs = check1Initial;
             bool remember  = check2Initial;
 
-            var win = new Window { Title = "KillerPDF", Width = 380, SizeToContent = SizeToContent.Height };
+            var win = new Window { Title = "MmdPdf", Width = 380, SizeToContent = SizeToContent.Height };
             // fade:false - the app's own fade-out follows immediately on confirm; two fades
             // back-to-back read as lag (same reasoning as the unsaved-changes prompt).
             DialogChrome.Configure(win, owner, fade: false);
@@ -376,7 +376,7 @@ namespace KillerPDF
 
             var root = new StackPanel();
 
-            // Title bar: the wordmark, exactly like Show()'s "KillerPDF" branch.
+            // Title bar: the wordmark, exactly like Show()'s "MmdPdf" branch.
             var titleBar = new Border
             {
                 Background = Application.Current.TryFindResource("UseDialogCaption") is true ? UiKit.Brush("TitleBarBrush") : Brushes.Transparent,
@@ -391,7 +391,7 @@ namespace KillerPDF
             wm.Children.Add(wmTb);
             titleBar.Child = wm;
             if (Application.Current.TryFindResource("UseDialogCaption") is true)
-                titleBar = DialogChrome.BuildTitleBar(win, owner, "KillerPDF", () => win.Close());
+                titleBar = DialogChrome.BuildTitleBar(win, owner, "MmdPdf", () => win.Close());
             titleBar.Height = Application.Current.TryFindResource("DialogTitleBarHeight") is double titleHeight ? titleHeight : double.NaN;
             root.Children.Add(titleBar);
 
@@ -504,7 +504,7 @@ namespace KillerPDF
             // Enter anywhere in the field submits.
             pw.KeyDown += (_, e) => { if (e.Key == Key.Enter) { result = pw.Password; win.Close(); } };
 
-            win.Content = DialogChrome.Frame(win, owner, "KillerPDF", CloseCancel, body);
+            win.Content = DialogChrome.Frame(win, owner, "MmdPdf", CloseCancel, body);
             win.Loaded += (_, _2) => pw.Focus();
             win.ShowDialog();
             return result;