Camera Zoom Gesture 3p/1p (Pinch) + Avatar Position + Joystick area

## **Description**
Implement the two-finger pinch gesture to switch between first-person and third-person camera, matching Roblox's mobile behavior. This requires defining the joystick's screen area first, so the pinch gesture zone can be set to cover the rest of the screen without conflicting with joystick input. Additionally, adjust the avatar's position (center it on screen) and reposition the crosshair so it no longer overlaps the avatar model.

## **📝 Deliverables:**

- [ ] Review and Adjust Joystick Input Area
- [ ] Two-finger pinch gesture controlling camera zoom distance in real time (third-person ↔ first-person)
- [ ] Avatar position: Avatar centered on screen
- [ ] Crosshair new position.

## **🔗 References:**
- [decentraland/godot-explorer#2642](https://github.com/decentraland/godot-explorer/issues/2642) — HUD + Social Panel Redesign Iteration #1, the change that introduced the left skew
- [decentraland/godot-explorer#2635](https://github.com/decentraland/godot-explorer/issues/2635) — HUD Iteration #2 visuals; final menu bounds must be settled against these
- [decentraland/godot-explorer#2343](https://github.com/decentraland/godot-explorer/issues/2343) — HUD positioning parity Android/iOS; offset must hold on both
- [decentraland/unity-explorer#611](https://github.com/decentraland/unity-explorer/pull/611) — desktop precedent: shoulder offset + forced center on unlocked cursor, plus configurable aim offsets
- [decentraland/unity-explorer#3666](https://github.com/decentraland/unity-explorer/issues/3666) — horizontal camera offset caused asymmetric wall clipping on desktop; regression guard for this change