URGENT FIX: Video player back button now works

Changed all router.dismissCoordinator() calls to router.popLast() in video player:
- Overlay.swift: Back button when confirming close
- VideoPlayer.swift: Auto-exit when video ends
- LoadingView.swift: Cancel button during loading

dismissCoordinator() only works with .fullScreen/.modal presentations.
Since we changed video player to .push navigation, we need popLast() instead.

This fixes ESC/menu button not working during video playback.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

jellypig tvOS/Views/VideoPlayer/Components/LoadingView.swift

@@ -28,7 +28,7 @@ extension VideoPlayer {
                     ProgressView()
 
                     Button {
-                        router.dismissCoordinator()
+                        router.popLast()
                     } label: {
                         Text(L10n.cancel)
                             .foregroundColor(.red)

jellypig tvOS/Views/VideoPlayer/Overlays/Overlay.swift

@@ -110,7 +110,7 @@ extension VideoPlayer {
 
             if isPresentingOverlay && currentOverlayType == .confirmClose {
                 proxy.stop()
-                router.dismissCoordinator()
+                router.popLast()
             } else if isPresentingOverlay && currentOverlayType == .smallMenu {
                 currentOverlayType = .main
             } else {

jellypig tvOS/Views/VideoPlayer/VideoPlayer.swift

@@ -60,7 +60,7 @@ struct VideoPlayer: View {
                         {
                             videoPlayerManager.selectNextViewModel()
                         } else {
-                            router.dismissCoordinator()
+                            router.popLast()
                         }
                     }
                 }