Prefer fast-loading formats when switching to AVPlayer

When switching from MPV to AVPlayer, prioritize HLS and stream formats over non-streamable MP4/AVC1 formats to avoid long loading times.

Changes:
- Added isFastLoadingFormat() helper to AVPlayerBackend
- Modified streamByQualityProfile to prefer fast-loading formats for AVPlayer
- Falls back to non-streamable formats only if no fast-loading option exists
- Ensures quick backend switching without waiting for metadata download

Model/Player/Backends/AVPlayerBackend.swift

@@ -178,6 +178,12 @@ final class AVPlayerBackend: PlayerBackend {
         return stream.kind == .hls || stream.kind == .stream
     }
 
+    func isFastLoadingFormat(_ stream: Stream) -> Bool {
+        // HLS and stream formats load quickly
+        // Non-streamable MP4/AVC1 formats may take a long time
+        return stream.kind == .hls || stream.kind == .stream
+    }
+
     func playStream(
         _ stream: Stream,
         of video: Video,

Model/Player/PlayerQueue.swift

@@ -133,6 +133,26 @@ extension PlayerModel {
 
         let profile = qualityProfile ?? .defaultProfile
 
+        // For AVPlayer, prefer fast-loading formats (HLS/stream) over non-streamable formats
+        // to avoid long loading times when switching backends
+        if activeBackend == .appleAVPlayer, let avBackend = backend as? AVPlayerBackend {
+            // Try to find a fast-loading stream first
+            let fastLoadingStreams = availableStreams.filter { backend.canPlay($0) && avBackend.isFastLoadingFormat($0) }
+            if let fastStream = backend.bestPlayable(
+                fastLoadingStreams.filter { profile.isPreferred($0) },
+                maxResolution: profile.resolution, formatOrder: profile.formats
+            ) {
+                return fastStream
+            }
+            // Fallback to any fast-loading stream
+            if let fastStream = backend.bestPlayable(
+                fastLoadingStreams,
+                maxResolution: profile.resolution, formatOrder: profile.formats
+            ) {
+                return fastStream
+            }
+        }
+
         // First attempt: Filter by both `canPlay` and `isPreferred`
         if let streamPreferredForProfile = backend.bestPlayable(
             availableStreams.filter { backend.canPlay($0) && profile.isPreferred($0) },