Fix Cinematic initialization and serialization bugs

[capdevon]

Refactors and Improves the Cinematic class

This pull request enhances the Cinematic class, focusing on better documentation, serialization improvements, and memory management. Key updates include:

• Improved Javadoc: Expanded and clarified class-level and method-level documentation for better developer understanding and usability.
• Serialization Refactor: Replaces custom array-based serialization of cinematic events with more robust SavableArrayList serialization/deserialization.
• App Reference: Adds an Application field to the class, initialized during initialize() and passed to event initialization for consistency.
• Camera Management: Introduces a new clearCameras() method to properly detach and clear all camera nodes from the scene, now called from cleanup() to avoid memory leaks.
• Cleanup Enhancements: Ensures the cinematic is properly reset on cleanup by resetting the initialized flag, clearing events, and removing camera nodes.
• Constructor and Parameter Documentation: Adds and improves JavaDoc for constructors and methods, clarifies parameter usage, and updates copyright.
• Minor Code and Comment Cleanups: Updates comments, fixes typos, improves formatting, and makes the cinematicEvents list non-final for deserialization.

These changes improve maintainability, clarity, and the robustness of cinematic lifecycle management in the engine.

Enhance AnimEvent Serialization and Model Handling

This PR introduces improvements to the AnimEvent class in the com.jme3.cinematic.events package by enhancing how animation events are associated with their models and how they are serialized/deserialized. The changes ensure more robust handling of AnimComposer and the associated Spatial model, especially when saving and loading animation events.

Key Changes

• Model Reference Added:
  Introduced a private Spatial model field to AnimEvent to keep track of the model associated with the animation event.
• Constructors Updated:
  • Added a new constructor to allow instantiation with default animation layer.
  • Modified constructors to initialize the model field from the AnimComposer.
• Initialization Logic Enhanced:
  In initEvent, if the composer is not set but the model is, the code attempts to retrieve the correct AnimComposer from the model, ensuring reliable initialization even after deserialization.
• Serialization Improvements:
  • The model field is now written to and read from the JME capsules, replacing the direct serialization of cinematic and composer fields (which are no longer serialized).
  • This approach improves the resilience of event saving/loading, especially when objects are reconstructed from files.
• Dispose Method Implemented:
  Added a custom dispose() method to clean up references to cinematic and composer when the event is disposed, aiding memory management.
• Copyright Update:
  Updated the copyright year.

Motivation

These changes address issues related to the persistence and restoration of animation events across sessions, improving the reliability of cinematic workflows in jMonkeyEngine. By serializing the model reference and reconstructing the composer as needed, the risk of null references or mismatched state is reduced.

Impact

• Improves the robustness of cinematic event handling.
• Enhances serialization/deserialization for animation events.

[codex128]

Closing because requested changes have not been addressed in a timely manner.

[github-actions]

🖼️ Screenshot tests have failed.

The purpose of these tests is to ensure that changes introduced in this PR don't break visual features. They are visual unit tests.

📄 Where to find the report:

• Go to the (failed run) > Summary > Artifacts > screenshot-test-report
• Download the zip and open jme3-screenshot-tests/build/reports/ScreenshotDiffReport.html

⚠️ If you didn't expect to change anything visual:
Fix your changes so the screenshot tests pass.

✅ If you did mean to change things:
Review the replacement images in jme3-screenshot-tests/build/changed-images to make sure they really are improvements and then replace and commit the replacement images at jme3-screenshot-tests/src/test/resources.

✨ If you are creating entirely new tests:
Find the new images in jme3-screenshot-tests/build/changed-images and commit the new images at jme3-screenshot-tests/src/test/resources.

Note; it is very important that the committed reference images are created on the build pipeline, locally created images are not reliable. Similarly tests will fail locally but you can look at the report to check they are "visually similar".

See https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-screenshot-tests/README.md for more information

Contact @richardTingle (aka richtea) for guidance if required