style(input): update default gamepad button layout to match NES ergonomics

- Reorder standard NES buttons and turbo mapping:
  - B/Y (Square) for NES B, A/A (Cross) for NES A
  - East (Circle) and North (Triangle) for Turbo A/B
- Remap system hotkeys:
  - Set L1/LB for Rewind and R1/RB for Fast Forward
  - Set Save, Load, Pause, and FullScreen to unassigned by default
- Synchronize default mapping across Rust backend and Flutter platform layers

Author: mikai233

crates/nesium-flutter/src/frb_generated.rs

@@ -26,7 +26,7 @@
 // Section: imports
 
 use flutter_rust_bridge::for_generated::byteorder::{NativeEndian, ReadBytesExt, WriteBytesExt};
-use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+use flutter_rust_bridge::for_generated::{Lifetimeable, Lockable, transform_result_dco};
 use flutter_rust_bridge::{Handler, IntoIntoDart};
 
 // Section: boilerplate
@@ -7673,7 +7673,7 @@ mod io {
     use flutter_rust_bridge::for_generated::byteorder::{
         NativeEndian, ReadBytesExt, WriteBytesExt,
     };
-    use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+    use flutter_rust_bridge::for_generated::{Lifetimeable, Lockable, transform_result_dco};
     use flutter_rust_bridge::{Handler, IntoIntoDart};
 
     // Section: boilerplate
@@ -7697,7 +7697,7 @@ mod web {
     };
     use flutter_rust_bridge::for_generated::wasm_bindgen;
     use flutter_rust_bridge::for_generated::wasm_bindgen::prelude::*;
-    use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+    use flutter_rust_bridge::for_generated::{Lifetimeable, Lockable, transform_result_dco};
     use flutter_rust_bridge::{Handler, IntoIntoDart};
 
     // Section: boilerplate

crates/nesium-support/src/gamepad.rs

@@ -70,16 +70,16 @@ pub struct ButtonMapping {
 impl Default for ButtonMapping {
     fn default() -> Self {
         Self {
-            a: Some(Button::South), // Xbox A / PS Cross
-            b: Some(Button::East),  // Xbox B / PS Circle
+            a: Some(Button::South), // A / Cross
+            b: Some(Button::West),  // Y / Square
             select: Some(Button::Select),
             start: Some(Button::Start),
             up: Some(Button::DPadUp),
             down: Some(Button::DPadDown),
             left: Some(Button::DPadLeft),
             right: Some(Button::DPadRight),
-            turbo_a: Some(Button::North), // Y / △ (Xbox Y / PS Triangle)
-            turbo_b: Some(Button::West),  // X / □ (Xbox X / PS Square)
+            turbo_a: Some(Button::East),  // B / Circle
+            turbo_b: Some(Button::North), // X / Triangle
         }
     }
 }
@@ -115,8 +115,8 @@ pub struct ActionMapping {
 impl Default for ActionMapping {
     fn default() -> Self {
         Self {
-            rewind: Some(Button::RightTrigger2),      // RT / R2
-            fast_forward: Some(Button::LeftTrigger2), // LT / L2
+            rewind: Some(Button::LeftTrigger),        // L1 / LB
+            fast_forward: Some(Button::RightTrigger), // R1 / RB
             save_state: None,
             load_state: None,
             pause: None,