🎨 Palette: Improved accessibility and tooltips in ProjectBar

[sachasayan]

This PR adds micro-UX improvements to the ProjectBar component to enhance accessibility and user delight.

💡 What:

• Integrated Tooltip from the project's design system for icon-only buttons.
• Added descriptive aria-label attributes to the "Save Project", "Close Project", and "Export Project to PDF" buttons.

🎯 Why:

• Icon-only buttons can be ambiguous for users. Tooltips provide immediate clarity on hover.
• ARIA labels ensure that users relying on screen readers can understand the purpose of each button, fulfilling the mission of making the UI more accessible.

♿ Accessibility:

• Every icon-only button in the ProjectBar now has a clear text alternative for assistive technologies.

🛠️ Verification:

• Unit tests passed (pnpm test).
• Production build succeeded (npx electron-vite build).
• Code reviewed to ensure no regressions in modal trigger functionality.
• pnpm-lock.yaml was explicitly removed to comply with repository constraints.

---

PR created automatically by Jules for task 2786061136768595900 started by @sachasayan

[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.