Feature Request: Add Animation Toggle and Performance Optimization

Current tile animations can feel sluggish or laggy, especially on lower-end devices. Overly long or heavy animations for merging and spawning tiles impact gameplay responsiveness. Players should have control over animation speed or disable them entirely for faster play.

### 🎯 Proposed Solution
- Add an **Animations Toggle** in the settings menu.
- Allow players to:
- Disable animations entirely.
- Choose between “Normal” and “Fast” animation modes.
- Optimize transition logic for smoother tile movement.

### ✅ Expected Behavior
- Players can toggle animation settings anytime.
- Fast/disabled animations improve responsiveness on all devices.
- Smooth visual transitions even under high-speed play.

### 🧪 Test Steps
1. Enable “Fast” mode → verify tile movement is quicker.
2. Disable animations → tiles move instantly with no lag.
3. Refresh page → ensure preference persists.