docs: add workspace switching animation

[Coasterpete]

Summary

This documentation update refreshes the project's README with current visuals from the Quantum CoasterWorks editor.

The previous screenshots no longer reflected the current state of the application. This update replaces them with recent captures from the M165 development milestone and adds an animated illustration of the workspace switching experience.

Changes

• Replaced outdated README screenshots with current editor screenshots.
• Added updated images for:
  • Track Workspace
  • Engineering Math Plots
  • Train Workspace
• Added an inline animated GIF demonstrating workspace switching.
• Added a link to a higher-quality MP4 recording of the same workspace switching sequence.
• Renamed the workspace switching recording to a descriptive filename.
• Updated screenshot captions and descriptions to match the current editor.

Notes

No application code, backend logic, or tests were modified.

This PR is documentation-only and is intended to improve the repository's presentation and accurately reflect the current state of the Quantum CoasterWorks editor.