Voice message: variable play back speed (#5121)

* Implement voice message variable playback speed

* Move playback speed string to Untranslated

https://github.com/element-hq/element-x-ios/pull/5121#discussion_r2822631371

* Address review feedback for voice message playback speed

- Persist voice message playback speed as an enum in AppSettings instead of storing an index.
- Update playback speed cycling to derive from enum allCases and safely fall back to `.default` if the stored value cannot be resolved.
- Apply runtime speed updates in AudioPlayer only when the player is in the `.playing` state.
- Keep MediaPlayerProviderTests formatting/indentation style intact while retaining mock playback speed setup.
- Regenerate preview snapshots for:
  - PlaybackSpeedButton
  - VoiceMessageRoomPlaybackView
  - VoiceMessageRoomTimelineView

* Move VoiceMessagePlaybackSpeed outside AppSettings, remove speedRatio

* Stabilize PlaybackSpeedButton width

* Sync voice-message speed label

- Add voiceMessagePlaybackSpeed to TimelineViewState and bind it from appSettings.$voiceMessagePlaybackSpeed.
- Pass that timeline-level speed into VoiceMessageRoomPlaybackView and use it for PlaybackSpeedButton, so labels update consistently across items.
- Use @EnvironmentObject in VoiceMessageRoomTimelineContent so the view re-renders when timeline context state changes.
- In WaveformInteractionModifier, add .allowsHitTesting(showCursor) to the cursor interaction view so hidden pre-playback cursor hit area does not steal taps from the speed button.

ElementX/Sources/Application/Settings/AppSettings.swift

@@ -82,6 +82,8 @@ final class AppSettings {
         case spaceSettingsEnabled
         case createSpaceEnabled
         
+        case voiceMessagePlaybackSpeed
+
         // Doug's tweaks 🔧
         case hideUnreadMessagesBadge
         case hideQuietNotificationAlerts
@@ -359,7 +361,10 @@ final class AppSettings {
     
     @UserPreference(key: UserDefaultsKeys.optimizeMediaUploads, defaultValue: true, storageType: .userDefaults(store))
     var optimizeMediaUploads
-    
+
+    @UserPreference(key: UserDefaultsKeys.voiceMessagePlaybackSpeed, defaultValue: VoiceMessagePlaybackSpeed.default, storageType: .userDefaults(store))
+    var voiceMessagePlaybackSpeed: VoiceMessagePlaybackSpeed
+
     /// Whether or not to show a warning on the media caption composer so the user knows
     /// that captions might not be visible to users who are using other Matrix clients.
     let shouldShowMediaCaptionWarning = true
@@ -447,3 +452,10 @@ final class AppSettings {
 }
 
 extension AppSettings: CommonSettingsProtocol { }
+
+enum VoiceMessagePlaybackSpeed: Float, CaseIterable, Codable {
+    case `default` = 1.0
+    case fast = 1.5
+    case fastest = 2.0
+    case slow = 0.5
+}