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/mod.rs

@@ -18,7 +18,10 @@ use crate::fighter::state::hitstun::HitstunState;
 use crate::fighter::surface::EcbLockPolicy;
 use crate::fighter::visual::FighterAnimations;
 use crate::fighter::{
-    Fighter, FighterDamage, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole, FighterInvulnerabilityState, FighterPendingRespawn, FighterPresentationSnap, FighterPreviousTranslation, FighterSurfaceState, FighterTranslation, FighterVelocity,
+    Fighter, FighterDamage, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop,
+    FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole,
+    FighterInvulnerabilityState, FighterPendingRespawn, FighterPresentationSnap,
+    FighterPreviousTranslation, FighterSurfaceState, FighterTranslation, FighterVelocity,
 };
 use crate::game_settings::GameSettings;
 use crate::input::FighterInput;
@@ -32,6 +35,7 @@ use crate::stage::line::StageCollision;
 use crate::stage::manifest::{StageManifest, StageManifestRegistry};
 
 pub mod air;
+pub mod air_attack;
 pub mod air_dodge;
 pub mod angel;
 pub mod crouch;
@@ -47,7 +51,6 @@ pub mod run;
 pub mod turn;
 pub mod wait;
 pub mod walk;
-pub mod air_attack;
 
 #[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum SurfacePolicy {
@@ -170,6 +173,7 @@ impl EnterContext<'_> {
 }
 
 pub struct ExitContext<'a> {
+    pub input: &'a mut FighterInput,
     pub hitboxes: &'a mut FighterHitboxes,
     pub surface: &'a mut FighterSurfaceState,
     pub vulnerability: &'a mut FighterInvulnerabilityState,
@@ -306,7 +310,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
             animation,
             surface: &self.surface,
             stage_collision,
-            attack_script_assets: attack_script_assets
+            attack_script_assets: attack_script_assets,
         }
     }
 
@@ -333,6 +337,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
 
     fn exit_context(&mut self) -> ExitContext<'_> {
         ExitContext {
+            input: &mut self.input,
             hitboxes: &mut self.hitboxes,
             surface: &mut self.surface,
             vulnerability: &mut self.vulnerability,
@@ -540,7 +545,7 @@ pub fn state_interrupt_system(
                 &baked_animations,
                 &manifest.attributes,
                 &stage_collision,
-                attack_script_assets
+                attack_script_assets,
             ))
         };