Phase A: stability and performance

A1 Pooled particle system
- New ParticleManager owns 9 reusable Phaser emitters created once per scene
  (jump, explosion, powerup, puff, sparks, flame, wind, spring, speedline)
- BootScene generates reusable white textures (px_square/soft/streak/ring)
- GameScene burst helpers + EffectsManager flow effects now delegate to the
  pool instead of allocating rectangles + tweens every frame
- Quality auto-detect (low on mobile/small screens) cuts particle counts

A2 Fix high-speed landing tunneling
- Cap downward velocity at PHYSICS.maxFallSpeed (boosts unaffected)
- platformCollisionFilter now uses a swept deltaY one-way check so a fast
  fall can never be wrongly rejected or passed through

A3 Safe storage
- New utils/storage.js wraps localStorage with in-memory fallback so private
  mode / quota errors cannot crash the game; all access routed through it

A4-A6 Lifecycle and robustness
- Global error / unhandledrejection guard recovers to the menu
- GameScene auto-pauses on tab hidden and cleans up the cross-scene listener
  on shutdown; fps pacing + disableContextMenu in game config
- Moving platforms use a proper dynamic body instead of destroy()+new Body

Verified in-browser: menu + game load with zero console errors, all emitters
active, normal bouncing works, fall speed capped.

src/entities/Platform.js

@@ -4,7 +4,10 @@ export class Platform extends Physics.Arcade.Sprite {
   constructor(scene, x, y, type = 'stable') {
     super(scene, x, y, 'platform');
     scene.add.existing(this);
-    scene.physics.add.existing(this, true);
+
+    // Moving platforms need a dynamic body; everything else is static.
+    const isMoving = type === 'moving';
+    scene.physics.add.existing(this, !isMoving);
 
     this.platformType = type;
     this.breakingState = 0;
@@ -13,12 +16,10 @@ export class Platform extends Physics.Arcade.Sprite {
     this.startX = x;
     this.glowTween = null;
 
-    if (type === 'moving') {
-      this.body.destroy();
-      this.body = new Phaser.Physics.Arcade.Body(scene.physics.world, this);
-      this.body.allowGravity = false;
-      this.body.immovable = true;
-      this.moveSpeed = Phaser.Math.Between(50, 120) * (Math.random() < 0.5 ? 1 : -1);
+    if (isMoving) {
+      this.body.setAllowGravity(false);
+      this.body.setImmovable(true);
+      this.moveSpeed = Phaser.Math.Between(50, 120) * (Phaser.Math.RND.frac() < 0.5 ? 1 : -1);
       this.moveRange = Phaser.Math.Between(60, 160);
     } else if (type === 'breaking') {
       this.setTint(0x999999);