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/core/graph/NodeRegistry.ts

@@ -56,6 +56,11 @@ export interface NodeContext {
    * stands for itself; any other entity stands for its direct collider children.
    */
   isTouching(a: EntityHandle, b: EntityHandle): boolean;
+  /**
+   * Moves `target` by (dx, dy) in local units, stopping its solid colliders at other solid
+   * colliders axis by axis (x first, then y) so it slides along walls. Reports which axes hit.
+   */
+  moveAndSlide(target: EntityHandle, dx: number, dy: number): { blockedX: boolean; blockedY: boolean };
   log(message: string): void;
   destroy(target: EntityHandle): void;
   stop(): void;