🎨 Palette: Add explicit controls and ARIA labels to Mario Game

[EiJackGH]

What:
Added visible keyboard instructions ("Press Space or Up Arrow to jump") and ARIA live region attributes to the Mario game score counter. Also fixed requirements.txt which had an invalid standard module entry (venv) blocking installation.

Why:
Previously, the game controls were hidden in the JavaScript, meaning users had to guess how to play. Furthermore, as the game score increased dynamically, screen reader users would not be notified of their progress.

Before/After:
(See verification screenshot)

Accessibility:

• Added aria-live="polite" and aria-atomic="true" to #score so dynamic score changes are announced to screen readers.
• Ensured keyboard instructions have sufficient color contrast against the game background.

---

PR created automatically by Jules for task 17957378885300877222 started by @EiJackGH

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.