improve bus compartment re-boarding logic and wall thickness

- Add `isSettledRelativeToChassis()` to measure settling speed relative to the bus instead of absolute world velocity, allowing kids resting inside a moving bus to re-board properly
- Gate re-boarding on being within the compartment's horizontal width to prevent false positives from kids resting on the ground at the bus's height
- Use a separate settling timer (`_slowSinceRelative`) to prevent interference between absolute and relative settle checks
- Increase `compartmentWallThickness` to 16 for better physical collision response against fast-moving kids

src/config.js

@@ -49,7 +49,10 @@ export const BUS = {
   // back below it while inside compartmentHalfWidth re-contains the kid.
   // Tune by playtesting - not physically derived.
   compartmentHalfWidth: 75 * WORLD_SCALE,
-  compartmentWallThickness: 10 * WORLD_SCALE,
+  // A bit thicker than the floor - gives a fast-moving kid more physical
+  // wall to hit before KidManager's per-tick clamp is what's actually
+  // stopping it, rather than the fixture itself.
+  compartmentWallThickness: 16 * WORLD_SCALE,
   compartmentFloorThickness: 10 * WORLD_SCALE,
   compartmentFloorY: 12 * WORLD_SCALE,
   compartmentTopY: -60 * WORLD_SCALE,

src/entities/Kid.js

@@ -13,6 +13,7 @@ export default class Kid {
     this.seatIndex = seatIndex;
     this.state = 'aboard'; // aboard | ejected
     this._slowSince = null; // see isSettled()
+    this._slowSinceRelative = null; // see isSettledRelativeToChassis()
 
     const worldPos = bus.getSeatWorldPosition(seatIndex);
 
@@ -91,6 +92,26 @@ export default class Kid {
     return now - this._slowSince >= KID.settleDurationMs;
   }
 
+  // Same idea as isSettled, but measured relative to the chassis's own
+  // velocity rather than the world - a kid at rest inside a moving bus
+  // shares the bus's velocity, which is almost always well above
+  // restSpeedThreshold, so gating re-boarding on isSettled's absolute speed
+  // would mean a kid resting inside the compartment while the bus drives
+  // could never actually re-board. Kept as its own method with its own
+  // timer (not a parameter on isSettled) since KidManager and PlayScene call
+  // these in the same tick with different references - sharing one timer
+  // between them would have each call reset the other's progress.
+  isSettledRelativeToChassis(now, chassisVelocity) {
+    const v = this.image.body.velocity;
+    const speed = Math.hypot(v.x - chassisVelocity.x, v.y - chassisVelocity.y);
+    if (speed >= KID.restSpeedThreshold) {
+      this._slowSinceRelative = null;
+      return false;
+    }
+    if (this._slowSinceRelative === null) this._slowSinceRelative = now;
+    return now - this._slowSinceRelative >= KID.settleDurationMs;
+  }
+
   destroy() {
     this.image.destroy();
   }

src/systems/KidManager.js

@@ -49,7 +49,7 @@ export default class KidManager {
   // chassis's own rotated frame. A kid drifting up past the open top
   // becomes ejected immediately. A floating kid drifting back down through
   // the open top only re-boards once it has actually come to rest inside
-  // the compartment (see Kid.isSettled), so a kid still mid-arc can't
+  // the compartment (see Kid.isSettledRelativeToChassis), so a kid still mid-arc can't
   // teleport back in mid-air.
   _onAfterUpdate() {
     const chassis = this.bus.chassis;
@@ -62,19 +62,29 @@ export default class KidManager {
 
       const dx = kid.image.x - chassis.x;
       const dy = kid.image.y - chassis.y;
+      const localX = dx * cos + dy * sin;
       const localY = -dx * sin + dy * cos;
       const isAboveOpenTop = localY < BUS.compartmentTopY;
+      // Re-boarding additionally requires being within the compartment's
+      // horizontal span, not just below the open top - localY alone can't
+      // tell "resting inside the compartment" apart from "resting on the
+      // ground anywhere else in the level at roughly the bus's height,"
+      // since compartmentTopY is measured purely along the chassis's local Y
+      // axis with no horizontal extent to it.
+      const isWithinCompartmentWidth = Math.abs(localX) <= BUS.compartmentHalfWidth;
 
       if (isAboveOpenTop && kid.state === 'aboard') {
         kid.markEjected();
         playRandomKidFallSound(this.scene);
         anyChanged = true;
-      } else if (!isAboveOpenTop && kid.state === 'ejected' && kid.isSettled(this.scene.time.now)) {
-        // Re-boarding is gated on the kid actually settling (see Kid.isSettled),
-        // not just passing through the compartment's vertical band again. Ejected
-        // kids run under reduced gravity, so a kid still floating/arc-ing will
-        // happily drift back through the open top while airborne; without this
-        // gate it would flip back to aboard mid-air and "teleport" back in.
+      } else if (!isAboveOpenTop && isWithinCompartmentWidth && kid.state === 'ejected' &&
+        kid.isSettledRelativeToChassis(this.scene.time.now, chassis.body.velocity)) {
+        // Re-boarding is gated on the kid actually settling relative to the
+        // chassis (see Kid.isSettledRelativeToChassis), not just passing
+        // through the compartment's open top again. Ejected kids run under
+        // reduced gravity, so a kid still floating/arc-ing will happily
+        // drift back through the open top while airborne; without this gate
+        // it would flip back to aboard mid-air and "teleport" back in.
         kid.markAboard();
         anyChanged = true;
       }