feat(desktop): GPU rendering, modern GTK4 UI, hotkeys and player 2

- Replace Cairo DrawingArea with custom NesScreen widget using
  GskTextureScaleNode for GPU-accelerated nearest-neighbor rendering
- Migrate from FileChooserNative to FileDialog (GTK 4.10+)
- Add AlertDialog for error display, structured logging via env_logger
- Add FPS counter (F3), NTSC/PAL toggle (F7), fullscreen (F11),
  Esc to quit, save/load state (Ctrl+S/L), volume slider
- Add player 2 keyboard input support
- Fix window proportions by compensating for header bar height

crates/nesemu-desktop/Cargo.toml

@@ -5,6 +5,8 @@ edition = "2024"
 
 [dependencies]
 nesemu = { path = "../.." }
-gtk4 = "0.8"
-cairo-rs = "0.19"
+gtk4 = { version = "0.8", features = ["v4_10"] }
+
 cpal = "0.15"
+log = "0.4"
+env_logger = "0.11"