Update SwiftFormat rules to properly format decimal numbers

[graycampbell]

📝 Summary

• Added --decimalgrouping option to .swiftformat to fix how decimal numbers are formatted.

🛠️ Type of Change

• Bug fix (change that fixes an issue)
• New feature (change that adds functionality)
• Breaking change (bug fix or feature that is not backwards compatible)
• Documentation (DocC, API docs, markdown files, templates, etc.)
• Testing (new tests, updated tests, etc.)
• Refactoring or code formatting (no logic changes)
• Updating dependencies (Swift packages, Homebrew, etc.)
• CI/CD (change to automated workflows)
• Chore (other maintenance)

🧪 How Has This Been Tested?

• All existing tests pass.

✅ Checklist

• I have added relevant tests
• I have verified all tests pass
• I have formatted my code using SwiftFormat
• I have updated documentation (if needed)
• I have added the appropriate label to my PR
• I have read the contributing guidelines
• I agree to follow this project's Code of Conduct

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.65%. Comparing base (8a1acea) to head (d2458a3).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #123   +/-   ##
=======================================
  Coverage   69.65%   69.65%           
=======================================
  Files          73       73           
  Lines        4811     4811           
=======================================
  Hits         3351     3351           
  Misses       1460     1460           

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