Conceptual unit tests for the Spacequest codebase.

[r3econ]

This commit introduces a comprehensive suite of XCTest unit tests covering the majority of the Swift files in your Spacequest project.

Due to limitations in my current execution environment, these tests are conceptual. They have been written to verify the logical structure, setup, and intended behavior of classes and methods but have not been compiled or run.

Key areas covered:

• Core game models (Spaceship, PlayerSpaceship, EnemySpaceship, Missile)
• UI elements and HUD components (Button, Joystick, LifeIndicator, ScoresNode)
• Game scenes (GameScene, MainMenuScene, GameOverScene, MenuScene) with conceptual testing for scene lifecycle and physics interactions.
• View controllers and managers (GameViewController, AnalyticsManager, MusicManager) with conceptual testing for UIKit and AVFoundation interactions.
• AppDelegate

Mock objects and specific XCTest assertions have been used to test logic flow where possible. Comments and XCTPass messages are included throughout the tests to highlight assumptions made and the conceptual nature of certain assertions.

These tests provide a foundational layer of test coverage that you can validate and expand upon in a macOS development environment.