[Docs] Better readme

[Xmaster6y]

What does this PR do?

Key insights about the PR.

Linked Issues

• Closes #?
• #?

Checklist

• I have read the CONTRIBUTING guide.
• I have added tests for my changes if needed.
• I have updated the documentation if needed.

---

Summary by cubic

Polished the README header by centering the logo and title, and added an arXiv badge linking to the paper. This makes the top section cleaner and highlights the publication alongside existing badges.

^{Written for commit baee621. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Auto-approved: Small doc update with additional badge and formatting; no risks or behavioral changes.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.50%. Comparing base (093a1e7) to head (baee621).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #36   +/-   ##
=======================================
  Coverage   96.50%   96.50%           
=======================================
  Files          29       29           
  Lines        1916     1916           
=======================================
  Hits         1849     1849           
  Misses         67       67           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.