Add Allow Software-Decoded Formats playback setting

Lets the auto stream selector pick formats whose codec isn't hardware
decoded on the current device. Defaults off; when on, 4K VP9/AV1 can be
auto-selected on Apple TV models without those decoders. Software-decoded
streams also move into the Recommended section so the selection stays
visible without enabling advanced stream details.

Yattee/Core/Settings/SettingsKey.swift

@@ -25,6 +25,7 @@ enum SettingsKey: String, CaseIterable {
     case preferredSubtitlesLanguage
     case resumeAction
     case tvOSMenuButtonClosesVideo
+    case allowSoftwareDecodedFormats
 
     // SponsorBlock
     case sponsorBlockEnabled
@@ -129,7 +130,7 @@ enum SettingsKey: String, CaseIterable {
     /// in both UserDefaults and iCloud, so each platform family syncs independently.
     var isPlatformSpecific: Bool {
         switch self {
-        case .preferredQuality, .cellularQuality, .macPlayerMode, .listStyle,
+        case .preferredQuality, .cellularQuality, .allowSoftwareDecodedFormats, .macPlayerMode, .listStyle,
              // Home layout — different UI paradigms per platform
              .homeShortcutOrder, .homeShortcutVisibility, .homeShortcutLayout,
              .homeSectionOrder, .homeSectionVisibility, .homeSectionItemsLimit, .homeSectionLayout,

Yattee/Core/Settings/SettingsManager+Playback.swift

@@ -75,6 +75,20 @@ extension SettingsManager {
         }
     }
 
+    /// When enabled, the auto stream selector will consider video formats whose codec
+    /// is not hardware-decodable on this device. Disabled by default. Useful on Apple TV
+    /// where 4K VP9/AV1 is otherwise excluded from auto-selection.
+    var allowSoftwareDecodedFormats: Bool {
+        get {
+            if let cached = _allowSoftwareDecodedFormats { return cached }
+            return bool(for: .allowSoftwareDecodedFormats, default: false)
+        }
+        set {
+            _allowSoftwareDecodedFormats = newValue
+            set(newValue, for: .allowSoftwareDecodedFormats)
+        }
+    }
+
     /// Preferred audio language code (e.g., "en", "de", "ja").
     /// When set, audio streams in this language will be auto-selected and shown first.
     /// nil means no preference (use original/default audio).

Yattee/Core/SettingsManager.swift

@@ -40,6 +40,7 @@ final class SettingsManager {
     var _playerVolume: Float?
     var _resumeAction: ResumeAction?
     var _tvOSMenuButtonClosesVideo: Bool?
+    var _allowSoftwareDecodedFormats: Bool?
 
     // SponsorBlock
     var _sponsorBlockEnabled: Bool?
@@ -413,6 +414,7 @@ final class SettingsManager {
         _playerVolume = nil
         _resumeAction = nil
         _tvOSMenuButtonClosesVideo = nil
+        _allowSoftwareDecodedFormats = nil
         _sponsorBlockEnabled = nil
         _sponsorBlockCategories = nil
         _sponsorBlockAPIURL = nil