🎨 Palette: Improve input responsiveness and tactile feedback

[aidasofialily-cmd]

💡 What:

• Extracted UI rendering into a render_ui helper function.
• Implemented immediate UI updates upon keypress for instant feedback.
• Replaced sleep_for with a dynamic poll timeout for better responsiveness.
• Cleaned up Hard Mode toggle output to stay in-place.

🎯 Why:

• The previous implementation had visible latency (up to 10ms) and the score wouldn't update visually until the next automatic tick.
• Toggling Hard Mode would print messy new lines, breaking the single-line UI pattern.

♿ Accessibility:

• The centralized rendering and removal of intermediate newlines create a cleaner and more stable terminal output.

---

PR created automatically by Jules for task 9726238982209391081 started by @aidasofialily-cmd

[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.