Fix ledge transitions and root motion loops (#91)

## Summary

- resolve each ledge action to the walkable segment on the stage-interior side
- preserve repeating root-motion displacement across every animation cycle
- add regression coverage for left/right ledge segments and multiple root-motion wraps
- Implement ledge intangibility

Reviewed-on: #91
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/baked_animation/mod.rs

@@ -487,7 +487,7 @@ mod tests {
     }
 
     #[test]
-    fn repeating_root_motion_preserves_cycle_displacement_at_wrap() {
+    fn repeating_root_motion_preserves_cycle_displacement_at_every_wrap() {
         let names = ["root".into()];
         let parents = [None];
         let pose = |x| FixedMat4::IDENTITY.with_translation(FGVec3::lit(x, "0", "0"));
@@ -498,7 +498,13 @@ mod tests {
             repeat: true,
         };
 
-        for (frame_number, x) in [(0, "0"), (1, "1")] {
+        for (frame_number, x, expected_delta) in [
+            (0, "0", FGVec3::ZERO),
+            (1, "1", FGVec3::lit("1", "0", "0")),
+            (2, "0", FGVec3::lit("1", "0", "0")),
+            (3, "1", FGVec3::lit("1", "0", "0")),
+            (4, "0", FGVec3::lit("1", "0", "0")),
+        ] {
             matrices.set_pose_with_frame(
                 frame(frame_number),
                 Some(0),
@@ -511,20 +517,8 @@ mod tests {
                 &[pose(x)],
                 FGi32::ONE,
             );
+            assert_eq!(matrices.root_motion_delta(), expected_delta);
         }
-        matrices.set_pose_with_frame(
-            frame(2),
-            Some(0),
-            Some(FGVec3::ZERO),
-            FGVec3::lit("2", "0", "0"),
-            Some(2),
-            AnimKind::Wait,
-            &names,
-            &parents,
-            &[pose("0")],
-            FGi32::ONE,
-        );
-        assert_eq!(matrices.root_motion_delta(), FGVec3::lit("1", "0", "0"));
     }
 
     #[test]

src/fighter/baked_animation/runtime.rs

@@ -110,6 +110,9 @@ impl BakedFighterAnimations {
             .get(&kind)
             .and_then(|index| self.clips.get(*index))
     }
+    pub fn get_animation_duration(&self, kind: AnimKind) -> Option<usize> {
+        self.clip(kind).map(|clip| clip.frames.len())
+    }
 }
 
 #[derive(Component, Clone, Debug, Default, Hash)]
@@ -411,7 +414,9 @@ impl FighterBoneMatrices {
                     previous.kind == animation_frame.kind
                         && previous.frame.saturating_add(1) == animation_frame.frame
                 })
-                && root_motion_loop_frame_count == Some(animation_frame.frame)
+                && root_motion_loop_frame_count.is_some_and(|loop_frame_count| {
+                    loop_frame_count > 0 && animation_frame.frame % loop_frame_count == 0
+                })
             {
                 delta = delta + root_motion_cycle_delta;
             }