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/Screens/Timeline/TimelineInteractionHandler.swift

@@ -417,7 +417,21 @@ class TimelineInteractionHandler {
     }
     
     // MARK: Audio Playback
-    
+
+    func changePlaybackSpeed(for itemID: TimelineItemIdentifier) {
+        let availableSpeeds = VoiceMessagePlaybackSpeed.allCases
+        guard let currentIndex = availableSpeeds.firstIndex(of: appSettings.voiceMessagePlaybackSpeed) else {
+            appSettings.voiceMessagePlaybackSpeed = .default
+            audioPlayerState(for: itemID)?.setPlaybackSpeed(VoiceMessagePlaybackSpeed.default.rawValue)
+            return
+        }
+
+        let nextIndex = (currentIndex + 1) % availableSpeeds.count
+        let nextSpeed = availableSpeeds[nextIndex]
+        appSettings.voiceMessagePlaybackSpeed = nextSpeed
+        audioPlayerState(for: itemID)?.setPlaybackSpeed(nextSpeed.rawValue)
+    }
+
     func playPauseAudio(for itemID: TimelineItemIdentifier) async {
         MXLog.info("Toggle play/pause audio for itemID \(itemID)")
         guard let timelineItem = timelineController.timelineItems.firstUsingStableID(itemID) else {
@@ -447,6 +461,7 @@ class TimelineInteractionHandler {
         // Ensure this one is attached
         if !audioPlayerState.isAttached {
             audioPlayerState.attachAudioPlayer(audioPlayer)
+            audioPlayerState.setPlaybackSpeed(appSettings.voiceMessagePlaybackSpeed.rawValue)
         }
 
         // Detach all other states