Multi-res grid refinement + Neon backend support

[hsalehipour]

Contributing Guidelines

• I have read and understood the CONTRIBUTING.md guidelines

Description

Grid refinement capability is now supported in XLB through the Neon backend. The Neon backend provides full support for dense grids on multi-GPU systems, as well as multi-resolution grids on single GPUs. All newly introduced functionalities have been carefully tested and optimized. This represents a major enhancement to the library and involves substantial additions and improvements to the codebase.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• All pytest tests pass

============================================= test session starts ==============================================
platform linux -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0
rootdir: /home/max/repo/test/XLB
collected 93 items                                                                                             

tests/boundary_conditions/bc_equilibrium/test_bc_equilibrium_jax.py ....                                 [  4%]
tests/boundary_conditions/bc_equilibrium/test_bc_equilibrium_warp.py ....                                [  8%]
tests/boundary_conditions/bc_fullway_bounce_back/test_bc_fullway_bounce_back_jax.py ......               [ 15%]
tests/boundary_conditions/bc_fullway_bounce_back/test_bc_fullway_bounce_back_warp.py ......              [ 21%]
tests/boundary_conditions/mask/test_bc_indices_masker_jax.py .......                                     [ 29%]
tests/boundary_conditions/mask/test_bc_indices_masker_warp.py ......                                     [ 35%]
tests/grids/test_grid_jax.py .......                                                                     [ 43%]
tests/grids/test_grid_warp.py ....                                                                       [ 47%]
tests/kernels/collision/test_bgk_collision_jax.py ......                                                 [ 53%]
tests/kernels/collision/test_bgk_collision_warp.py ......                                                [ 60%]
tests/kernels/equilibrium/test_equilibrium_jax.py ......                                                 [ 66%]
tests/kernels/equilibrium/test_equilibrium_warp.py ......                                                [ 73%]
tests/kernels/macroscopic/test_macroscopic_jax.py ......                                                 [ 79%]
tests/kernels/macroscopic/test_macroscopic_warp.py .......                                               [ 87%]
tests/kernels/stream/test_stream_jax.py ......                                                           [ 93%]
tests/kernels/stream/test_stream_warp.py ......                                                          [100%]

======================================== 93 passed in 248.34s (0:04:08) ========================================

Linting and Code Formatting

Make sure the code follows the project's linting and formatting standards. This project uses Ruff for linting.

To run Ruff, execute the following command from the root of the repository:

ruff check .

• Ruff passes