Refactor and Optimize snap_psibeta_half_tddft (#6765)

* Optimize snap_psibeta_half_tddft for better performance

Key optimizations include:
1. Cache Gauss-Legendre Grid: Implemented thread-safe caching for radial integration grid points and weights.
2. Precompute Spherical Harmonics: Precomputed Ylm and A dot r on the Lebedev angular grid to reduce inner loop overhead.
3. Memory Optimization: Lifted vector allocations out of loops and reused buffers to minimize allocation costs.
4. Inline Interpolation: Inlined polynomial interpolation and used precomputed inverse step size to avoid divisions.
5. Common Subexpression Elimination: Extracted invariant factors from the innermost loop to reduce arithmetic operations.

* Refactor snap_psibeta_half_tddft: improved code structure, added comments, and consolidated optimizations

* Fix off-by-one error in radial interpolation boundary check

Author: dzzz2001