Fix fighter visuals after landing snap (#67)

## Summary

- Mark landing position corrections as presentation discontinuities.
- Render and frame fighters from the current position for the snap frame.
- Keep previous translation history unchanged for gameplay collision and attack logic.

Reviewed-on: #67
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/mod.rs

@@ -29,7 +29,8 @@ pub use attributes::FighterAttributes;
 pub use ecb::FighterECB;
 pub use manifest::FighterId;
 pub use motion::{
-    FighterPreviousFacingDirection, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
+    FighterPresentationSnap, FighterPreviousFacingDirection, FighterPreviousTranslation,
+    FighterTranslation, FighterVelocity,
 };
 pub use surface::FighterSurfaceState;
 
@@ -147,6 +148,10 @@ impl Plugin for FighterPlugin {
     fn build(&self, app: &mut App) {
         app.add_plugins(FighterAttackPlugin)
             // Every state gets a chance to interrupt itself, in priority order.
+            .add_systems(
+                GgrsSchedule,
+                motion::clear_fighter_presentation_snaps.in_set(GameplaySet::Input),
+            )
             .add_systems(
                 GgrsSchedule,
                 (
@@ -202,6 +207,8 @@ impl Plugin for FighterPlugin {
             .checksum_component_with_hash::<FighterTranslation>()
             .rollback_component_with_copy::<FighterPreviousTranslation>()
             .checksum_component_with_hash::<FighterPreviousTranslation>()
+            .rollback_component_with_copy::<FighterPresentationSnap>()
+            .checksum_component_with_hash::<FighterPresentationSnap>()
             .rollback_component_with_copy::<FighterPreviousFacingDirection>()
             .checksum_component_with_hash::<FighterPreviousFacingDirection>()
             .rollback_component_with_copy::<animation::FighterAnimationFrame>()
@@ -304,6 +311,7 @@ pub fn spawn_fighter(
                 FighterVelocity::default(),
                 FighterTranslation(spawn_position),
                 FighterPreviousTranslation(spawn_position),
+                FighterPresentationSnap::default(),
             ),
             visual_root,
             animations,