Split home shortcut card style into Layout, Color, and Palette

Decouple the two concerns that were entangled in a single card-style setting:

- Layout (Compact / Regular) now only controls positioning of the
  icon / title / subtitle / counter.
- Color (Soft / Vibrant) is a new independent setting: Soft = tinted
  background with palette-colored icon and neutral text; Vibrant =
  solid palette fill with white icon/text.
- Palette (Accent first, then Classic/Sunset/Meadow/Berry/Grape/Custom)
  now applies to both layouts and both colors, and is always shown.

Adds section headers (Layout / Color / Palette) to the style page and
fixes the Compact preview to show the count subtitle line. Default is
Regular + Soft + Accent.

Yattee/Views/Home/HomeView.swift

@@ -402,12 +402,14 @@ struct HomeView: View {
         #endif
     }
 
-    /// Resolves the colorful-style color for a shortcut at the given grid
-    /// position from the selected palette (and custom colors when applicable).
+    /// Resolves the Regular-style fill color for a shortcut at the given grid
+    /// position from the selected palette (custom colors and accent color when
+    /// applicable).
     private func colorfulColor(atPosition position: Int) -> Color {
-        let palette = settingsManager?.homeShortcutColorfulPalette ?? .classic
+        let palette = settingsManager?.homeShortcutColorfulPalette ?? .accent
         let customHex = settingsManager?.homeShortcutCustomPaletteColors ?? []
-        return HomeShortcutColorfulPalette.color(forPosition: position, palette: palette, customHex: customHex)
+        let accentColor = settingsManager?.accentColor.color ?? .accentColor
+        return HomeShortcutColorfulPalette.color(forPosition: position, palette: palette, customHex: customHex, accentColor: accentColor)
     }
 
     private var shortcutsList: some View {