Add glass background theme setting for macOS control bar

Rename the macOS "Control Bar Buttons" settings entry to "Control Bar"
and add an Auto/Light/Dark glass background picker on that page. The
choice is stored per-preset as GlobalLayoutSettings.controlBarTheme and
forces the bar's glass color scheme via glassBackground(colorScheme:).

Yattee/Views/Player/macOS/MacOSControlBar.swift

@@ -80,7 +80,7 @@ struct MacOSControlBar: View {
         .padding(.horizontal, 16)
         .padding(.vertical, 10)
         .frame(maxWidth: 500)
-        .glassBackground(.regular, in: .rect(cornerRadius: 16))
+        .glassBackground(.regular, in: .rect(cornerRadius: 16), colorScheme: globalSettings.controlBarTheme.colorScheme)
         .shadow(color: .black.opacity(0.3), radius: 8, y: 4)
         // Seek preview overlay - positioned above the control bar
         .overlay(alignment: .bottom) {

Yattee/Views/Settings/PlayerControls/PlayerControlsSettingsView.swift

@@ -354,7 +354,7 @@ private struct LayoutSectionsSection: View {
                 HStack {
                     #if os(macOS)
                     Label(
-                        String(localized: "settings.playerControls.controlBarButtons", defaultValue: "Control Bar Buttons"),
+                        String(localized: "settings.playerControls.controlBar", defaultValue: "Control Bar"),
                         systemImage: "rectangle.bottomthird.inset.filled"
                     )
                     #else

Yattee/Views/Settings/PlayerControls/SectionEditorView.swift

@@ -15,6 +15,7 @@ struct SectionEditorView: View {
     // Local state for immediate UI updates
     @State private var buttons: [ControlButtonConfiguration] = []
     @State private var availableTypes: [ControlButtonType] = []
+    @State private var controlBarTheme: ControlsTheme = .system
 
     var body: some View {
         List {
@@ -45,6 +46,29 @@ struct SectionEditorView: View {
             .listRowBackground(Color.clear)
             #endif
 
+            // The macOS bar draws a glass capsule whose appearance can be forced.
+            #if os(macOS)
+            if sectionType == .bottom {
+                Section {
+                    Picker(
+                        String(localized: "settings.playerControls.glassBackground", defaultValue: "Glass Background"),
+                        selection: $controlBarTheme
+                    ) {
+                        ForEach(ControlsTheme.allCases, id: \.self) { theme in
+                            Text(glassBackgroundLabel(for: theme)).tag(theme)
+                        }
+                    }
+                    .disabled(!viewModel.canEditActivePreset)
+                    .onChange(of: controlBarTheme) { _, newTheme in
+                        guard newTheme != viewModel.currentLayout.globalSettings.controlBarTheme else { return }
+                        viewModel.updateGlobalSettingsSync { $0.controlBarTheme = newTheme }
+                    }
+                } header: {
+                    Text(String(localized: "settings.playerControls.appearance"))
+                }
+            }
+            #endif
+
             // Added buttons
             Section {
                 ForEach(buttons) { button in
@@ -139,6 +163,7 @@ struct SectionEditorView: View {
         case .bottom:
             buttons = preset.layout.bottomSection.buttons
         }
+        controlBarTheme = preset.layout.globalSettings.controlBarTheme
         syncAvailableTypes()
     }
 
@@ -160,12 +185,27 @@ struct SectionEditorView: View {
         viewModel.addButtonSync(buttonType, to: sectionType)
     }
 
+    #if os(macOS)
+    private func glassBackgroundLabel(for theme: ControlsTheme) -> String {
+        switch theme {
+        case .system:
+            return String(localized: "controls.theme.auto", defaultValue: "Auto")
+        case .light, .dark:
+            return theme.displayName
+        }
+    }
+    #endif
+
     private var sectionTitle: String {
         switch sectionType {
         case .top:
             return String(localized: "settings.playerControls.topButtons")
         case .bottom:
+            #if os(macOS)
+            return String(localized: "settings.playerControls.controlBar", defaultValue: "Control Bar")
+            #else
             return String(localized: "settings.playerControls.bottomButtons")
+            #endif
         }
     }
 }