Add MaxDeterminantGrid with full AngularGrid and AtomGrid integration

[alok-108]

Summary

Implemented MaxDeterminantGrid using maximum determinant (Fekete) points for spherical integration with positive weights and improved numerical stability.

Key Features

• Integrated with AngularGrid and AtomGrid
• • Supports both degree and size initialization
• • Uses precomputed datasets

Validation

• Verified sum weights = 4pi
• • Constant integration returns 4pi
• • Spherical harmonics validated across full range
• • All tests pass (79/79)

Fixes

• Corrected spherical harmonic test coverage
• • Fixed Sphinx math formatting
• • Added notebook integration via .nblink

Notes

All tests and documentation build successfully in a clean environment.

[alok-108]

Hi @PaulWAyers,

Would really appreciate your review whenever you get time. Happy to make any changes if needed!

[alok-108]

Hi @PaulWAyers,

Would really appreciate your review whenever you get time. Happy to make any changes if needed!