Add details panel preset settings UI and default visibility

Phase 2 of the player panels redesign:

- New "Details Panel" screen in Player Controls settings: page
  reorder/enable list with per-page editor (info element toggles),
  and a default panel visibility picker (hidden/visible/remember).
- PlayerControlsSettingsViewModel gains panelSettings bindings with
  the usual debounced-save flow; the last enabled page cannot be
  disabled.
- Built-in presets bumped to v9 with explicit default panelSettings.
- The preset's default visibility now drives the wide-layout panel
  on player open and on entering landscape, replacing the hard
  hidden resets; "remember" restores the new detailsPanelLastVisible
  setting recorded on user toggles. Applied once per expanded player
  session (flag on NavigationCoordinator survives re-mounts).
- WideScreenPlayerLayout picks up external visibility writes so the
  async-loaded default reaches the mounted layout.
- Unit tests for PanelSettings Codable compatibility (round-trip,
  old JSON, unknown page types/discriminators/enum values); removed
  stale PlayerInfoTab tests left from Phase 1.

Yattee/Models/PlayerControls/BuiltInPresets.swift

@@ -11,7 +11,7 @@ extension LayoutPreset {
     /// Bump this version whenever any built-in preset definition changes.
     /// On launch, the app compares this against the last-applied version
     /// and replaces stale built-in presets with fresh copies from code.
-    static let builtInPresetsVersion = 8
+    static let builtInPresetsVersion = 9
 
     // MARK: - Built-in Preset IDs
 
@@ -131,7 +131,8 @@ extension LayoutPreset {
             progressBarSettings: ProgressBarSettings(),
             gesturesSettings: gesturesSettings,
             playerPillSettings: playerPillSettings,
-            miniPlayerSettings: miniPlayerSettings
+            miniPlayerSettings: miniPlayerSettings,
+            panelSettings: .default
         )
     }
 
@@ -192,7 +193,8 @@ extension LayoutPreset {
             progressBarSettings: ProgressBarSettings(),
             gesturesSettings: nil,
             playerPillSettings: nil,
-            miniPlayerSettings: MiniPlayerSettings()
+            miniPlayerSettings: MiniPlayerSettings(),
+            panelSettings: .default
         )
     }
 
@@ -285,7 +287,8 @@ extension LayoutPreset {
             progressBarSettings: progressBarSettings,
             gesturesSettings: gesturesSettings,
             playerPillSettings: playerPillSettings,
-            miniPlayerSettings: miniPlayerSettings
+            miniPlayerSettings: miniPlayerSettings,
+            panelSettings: .default
         )
     }
 
@@ -336,7 +339,8 @@ extension LayoutPreset {
             progressBarSettings: progressBarSettings,
             gesturesSettings: nil,
             playerPillSettings: nil,
-            miniPlayerSettings: MiniPlayerSettings()
+            miniPlayerSettings: MiniPlayerSettings(),
+            panelSettings: .default
         )
     }
 

Yattee/Models/PlayerControls/PanelSettings.swift

@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import SwiftUI
 
 // MARK: - Panel Page Type
 
@@ -77,10 +78,22 @@ enum PanelLayoutMode: String, Codable, Sendable {
 // MARK: - Default Visibility
 
 /// Default panel visibility when the player opens on iPad/macOS.
-enum PanelDefaultVisibility: String, Codable, Sendable {
+enum PanelDefaultVisibility: String, Codable, CaseIterable, Sendable {
     case hidden
     case visible
     case remember
+
+    /// Localized name for the settings picker.
+    var displayName: String {
+        switch self {
+        case .hidden:
+            return String(localized: "panel.defaultVisibility.hidden")
+        case .visible:
+            return String(localized: "panel.defaultVisibility.visible")
+        case .remember:
+            return String(localized: "panel.defaultVisibility.remember")
+        }
+    }
 }
 
 // MARK: - Per-Page Settings
@@ -288,6 +301,12 @@ struct PanelSettings: Codable, Hashable, Sendable {
         self.showPageBarLabels = showPageBarLabels
     }
 
+    /// In-memory cache of the active preset's panel settings, refreshed by the
+    /// player whenever the layout loads. Lets synchronous appear paths (e.g.
+    /// default-visibility resets) read the last known value before the async
+    /// layout fetch completes.
+    nonisolated(unsafe) static var cached: PanelSettings = .default
+
     static let `default` = PanelSettings(pages: [
         PanelPageConfiguration(pageType: .info, region: .belowVideo),
         PanelPageConfiguration(pageType: .comments, region: .belowVideo),
@@ -328,6 +347,36 @@ struct PanelSettings: Codable, Hashable, Sendable {
         enabledPages().contains { $0.pageType == pageType }
     }
 
+    /// The stored configuration for a page type, if present.
+    func configuration(for pageType: PanelPageType) -> PanelPageConfiguration? {
+        normalizedPages.first { $0.pageType == pageType }
+    }
+
+    // MARK: - Mutations (settings UI)
+
+    /// Replaces the stored pages with the normalized list so mutations by
+    /// index operate on the same list the UI displays.
+    mutating func normalize() {
+        pages = normalizedPages
+    }
+
+    mutating func setEnabled(_ isEnabled: Bool, for pageType: PanelPageType) {
+        normalize()
+        guard let index = pages.firstIndex(where: { $0.pageType == pageType }) else { return }
+        pages[index].isEnabled = isEnabled
+    }
+
+    mutating func movePages(fromOffsets source: IndexSet, toOffset destination: Int) {
+        normalize()
+        pages.move(fromOffsets: source, toOffset: destination)
+    }
+
+    mutating func updateSettings(_ newSettings: PanelPageSettings?, for pageType: PanelPageType) {
+        normalize()
+        guard let index = pages.firstIndex(where: { $0.pageType == pageType }) else { return }
+        pages[index].settings = newSettings
+    }
+
     private enum CodingKeys: String, CodingKey {
         case pages
         case layoutMode