fix(text): show selected formatting and style controls

Use category-filtered font and selected-item dropdowns, separate horizontal and vertical alignment, and reuse the border-color palette templates for text color. Persist vertical alignment additively. Follow the established static text-source pattern: https://obsproject.com/kb/text-sources

Models/Source.cs

@@ -48,6 +48,13 @@ public enum TextLayerAlignment
     Right
 }
 
+public enum TextLayerVerticalAlignment
+{
+    Top,
+    Center,
+    Bottom
+}
+
 public enum ClipShape
 {
     Traditional,
@@ -423,9 +430,22 @@ public class Source : SceneElement
     public string TextColor
     {
         get => _textColor;
-        set => Set(ref _textColor, IsValidTextColor(value) ? value.ToUpperInvariant() : "#FFFFFF");
+        set
+        {
+            if (!Set(ref _textColor, IsValidTextColor(value) ? value.ToUpperInvariant() : "#FFFFFF")) return;
+            Raise(nameof(TextColorEntry));
+            Raise(nameof(TextColorOptions));
+        }
     }
 
+    public NamedColor TextColorEntry
+    {
+        get => BorderColorPalette.EntryFor(TextColor);
+        set => TextColor = value.Hex;
+    }
+
+    public IReadOnlyList<NamedColor> TextColorOptions => BorderColorPalette.OptionsFor(TextColor);
+
     private bool _textBold;
     public bool TextBold { get => _textBold; set => Set(ref _textBold, value); }
 
@@ -442,6 +462,14 @@ public class Source : SceneElement
         set => Set(ref _textAlignment, Enum.IsDefined(value) ? value : TextLayerAlignment.Left);
     }
 
+    private TextLayerVerticalAlignment _textVerticalAlignment;
+    public TextLayerVerticalAlignment TextVerticalAlignment
+    {
+        get => _textVerticalAlignment;
+        set => Set(ref _textVerticalAlignment,
+            Enum.IsDefined(value) ? value : TextLayerVerticalAlignment.Top);
+    }
+
     private static bool IsValidTextColor(string? value)
     {
         if (value is not { Length: 7 or 9 } || value[0] != '#') return false;