Trigger colliders and Move and slide against solid colliders

- Collider property isTrigger (no blocking, still reports enter/stay/exit)
- Node 'Move and slide' with blocked x/y outputs, axis-wise resolution
- axisSeparation/axisCorrection geometry for box/box, circle/circle, box/circle
- Amber outline for trigger colliders in the viewport
- Demo mover uses Move and slide; E2E step 15b, 7 new unit tests

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/runtime/systems/BehaviorSystem.ts

@@ -138,6 +138,14 @@ export class BehaviorSystem implements System {
         const eb = world.entities.find((e) => e === b || e.id === b.id);
         return Boolean(this.collisions && ea && eb && this.collisions.touching(world, ea, eb));
       },
+      moveAndSlide: (target, dx, dy) => {
+        const found = world.entities.find((e) => e === target || e.id === target.id);
+        if (!found) return { blockedX: false, blockedY: false };
+        if (this.collisions) return this.collisions.moveAndSlide(world, found, dx, dy);
+        found.x += dx;
+        found.y += dy;
+        return { blockedX: false, blockedY: false };
+      },
       log: (message) => {
         world.log.push(message);
         console.log(`[behavior ${entity.name}]`, message);