🎨 Palette: Add dynamic label and tooltip to Docker Prune button

[acebytes]

• 💡 What: Replaced the lone loading spinner with an HStack containing both a smaller spinner and "Pruning..." text when isDockerPruning is true. Added a .help() modifier to provide a context-aware tooltip for the button's standard and disabled states.
• 🎯 Why: Solves a UX issue where users might feel confused when the primary action button for Docker Prune becomes disabled without explicit visual/textual feedback about the ongoing process, especially during long-running tasks.
• 📸 Before/After: Before, just a spinning progress circle without text or tooltips; After, an explicit "Pruning..." text next to the spinner and helpful mouse hover tooltips for clarity.
• ♿ Accessibility: The .help() tooltip assists sighted mouse users in understanding the button's purpose and its disabled state context.

---

PR created automatically by Jules for task 11019854391611948885 started by @acebytes

[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.