feat: Functionally working stairs without sprite

- Made all observers public
- Observe all InteractionEvents in the app, not in the entity
- Added names to layout bundles
- Raised player speed to 4 m/s for quicker debugging
- Added second container on 2nd floor

src/layout/stairs.rs

@@ -0,0 +1,98 @@
+use bevy::{ecs::relationship::RelatedSpawner, prelude::*};
+use bevy_rapier2d::prelude::*;
+
+use crate::{meters, player::Player};
+
+use super::*;
+
+#[derive(Component, Debug, PartialEq, Eq, Default, Clone, Copy, Reflect)]
+#[reflect(Component, Debug, PartialEq, Default, Clone)]
+#[require(InteractiveObject, Collider, Sensor)]
+pub enum StairCollider {
+    #[default]
+    Up,
+    Down,
+}
+
+#[derive(Component, Clone, Copy, Default, Reflect, Debug, PartialEq)]
+#[reflect(Component, Clone, Default, Debug, PartialEq)]
+#[require(Transform)]
+pub struct Stairs {
+    pub up: Option<Vec2>,
+    pub down: Option<Vec2>,
+}
+
+pub fn on_stairs_interact(
+    event: On<InteractionEvent>,
+    collider_query: Query<(&ChildOf, &StairCollider)>,
+    stairs_query: Query<&Stairs>,
+    mut player_query: Query<&mut Transform, With<Player>>,
+) {
+    let Ok((parent, collider_type)) = collider_query.get(event.entity) else {
+        return;
+    };
+    let Ok(stairs) = stairs_query.get(parent.0) else {
+        error!("StairCollider does not have Stairs parent");
+        return;
+    };
+    let Ok(mut player_transform) = player_query.single_mut() else {
+        error!("Player is not single");
+        return;
+    };
+    
+    let offset = match collider_type {
+        StairCollider::Up => {
+            let Some(offset) = stairs.up else {
+                error!("StairCollider::Up triggered but Stairs.up is None");
+                return;
+            };
+            offset
+        },
+        StairCollider::Down => {
+            let Some(offset) = stairs.down else {
+                error!("StairCollider::Down triggered but Stairs.down is None");
+                return;
+            };
+            offset
+        },
+    };
+
+    player_transform.translation.x += offset.x;
+    player_transform.translation.y += offset.y;
+}
+
+pub fn stairs_bundle(
+    _asset_server: &Res<AssetServer>,
+    position: Vec2,
+    up_position: Option<Vec2>,
+    down_position: Option<Vec2>,
+) -> impl Bundle {
+    let (has_up, has_down) = (up_position.is_some(), down_position.is_some());
+    (
+        Stairs {
+            up: up_position,
+            down: down_position,
+        },
+        Transform::from_xyz(position.x, position.y, -1.),
+        Children::spawn(
+            SpawnWith(move |parent: &mut RelatedSpawner<ChildOf>| {
+                if has_up {
+                    parent.spawn((
+                        StairCollider::Up,
+                        Collider::cuboid(meters(1.), meters(1.)),
+                        Transform::from_xyz(meters(-1.), 0., 0.),
+                    ));
+                }
+
+                if has_down {
+                    parent.spawn((
+                        StairCollider::Down,
+                        Collider::cuboid(meters(1.), meters(1.)),
+                        Transform::from_xyz(meters(1.), 0., 0.),
+                    ));
+                }
+            })
+        ),
+        Name::new(format!("Stairs ({},{})", position.x, position.y))
+    )
+}