fix: code improvements

[dgawande12]

Pull Request: Refactor Swift Game Codebase for Maintainability and Performance

Overview

This PR refactors the Critter Carnival Swift codebase to address inefficiencies, improve maintainability, and follow best practices. The changes include architectural improvements, code deduplication, and enhanced game logic.

Key Changes

• Eliminated global variable pollution by introducing a GameManager singleton for score and state management.
• Removed code duplication by creating shared extensions for label creation, scene transitions, and background setup.
• Replaced magic numbers with organized constants in GameConstants.swift.
• Improved error handling and replaced force unwrapping with safe optional binding and guard statements.
• Enhanced game logic:
• Added proper player movement and boundary constraints.
• Implemented level progression and score milestones.
• Improved collision detection and explosion handling.
• Modernized touch handling using extension methods and switch statements.
• Consistent naming conventions and access control across all files.

Files Added

• GameConstants.swift: Centralized configuration and constants.
• GameManager.swift: Singleton for game state and score management.
• SKScene+Extensions.swift: Shared methods for all scenes.
• Benefits
• Improved performance and memory management.
• Easier to maintain and extend the codebase.
• Consistent architecture and code style.
• Production-ready and scalable for future features.

Reference
See CODE_IMPROVEMENTS.md for a detailed summary of all changes and benefits.