Rework input buffer to match HDR closer (#79)

## Summary

- Preserve distinct same-action bindings in rollback input frames.
- Add independent command lifetimes with tap and state-scoped hold buffering.
- Detect second shield bindings and consume shield commands for air dodge.
- Fix duplicate keyboard mappings being overwritten.

Reviewed-on: #79
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/state/air_dodge.rs

@@ -1,13 +1,17 @@
 use crate::{
     fighter::{
-        FighterInvulnerabilityState, animation::AnimKind, state::{
+        FighterInvulnerabilityState,
+        animation::AnimKind,
+        state::{
             CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
             UpdateContext,
             air::{self, AirborneStateCommon},
             fall::FallState,
             land::LandingType,
         },
-    }, input, math::vec::FGVec2,
+    },
+    input,
+    math::vec::FGVec2,
 };
 
 #[derive(Debug, Clone, Hash)]
@@ -29,8 +33,13 @@ impl FighterStateImpl for AirDodgeState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let airdodge_intangible_end = state_context.fighter_attributes.air_dodge_intangible_start + state_context.fighter_attributes.air_dodge_intangible_duration;
-        if state_context.animation_frame == state_context.fighter_attributes.air_dodge_intangible_start {
+        let airdodge_intangible_end = state_context.fighter_attributes.air_dodge_intangible_start
+            + state_context
+                .fighter_attributes
+                .air_dodge_intangible_duration;
+        if state_context.animation_frame
+            == state_context.fighter_attributes.air_dodge_intangible_start
+        {
             *state_context.vulnerability = FighterInvulnerabilityState::Intangible;
         } else if state_context.animation_frame >= airdodge_intangible_end {
             *state_context.vulnerability = FighterInvulnerabilityState::Vulnerable;
@@ -54,6 +63,13 @@ impl FighterStateImpl for AirDodgeState {
     fn on_enter(&mut self, state_context: &mut EnterContext) {
         state_context.play_animation(AnimKind::AirDodge, false);
 
+        state_context
+            .input
+            .clear_command(input::FighterCommands::Shield);
+        state_context
+            .input
+            .clear_command(input::FighterCommands::GuardHold);
+
         state_context.velocity.0 =
             self.direction * state_context.fighter_attributes.air_dodge_velocity;
     }
@@ -65,11 +81,11 @@ impl FighterStateImpl for AirDodgeState {
     fn surface_policy(&self) -> super::SurfacePolicy {
         super::SurfacePolicy::Airborne(crate::fighter::surface::EcbLockPolicy::StartOnDetach)
     }
-    
+
     fn on_exit(&mut self, state_context: &mut super::ExitContext) {
         *state_context.vulnerability = FighterInvulnerabilityState::Vulnerable;
     }
-    
+
     fn name(&self) -> String {
         Self::NAME.to_owned()
     }
@@ -79,7 +95,14 @@ pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {
     state_context
         .input
         .has_command(input::FighterCommands::Shield)
-        .then(|| {
+        .then_some(())
+        .or_else(|| {
+            state_context
+                .input
+                .has_command(input::FighterCommands::GuardHold)
+                .then_some(())
+        })
+        .map(|_| {
             FighterState::AirDodge(AirDodgeState {
                 direction: state_context
                     .input