Merge pull request #39 from gomlx/free

v0.7.3 Prevent destroying buffers for an already destroyed client.

Updated CHANGELOG, bumped version number.

Many refactorings, cleanups and updates.

* Updated Go dependency to go1.24: needed for the safer `runtime.AddCleanUp` used in `pjrt` now.
* Moved internal packages under a `internal` subdirectory, including code generating commands.
* Fixed the issue where Client objects never got garbage collected, due to cycles in finalizers.
  * Internal refactoring changing `runtime.SetFinalizer` to `runtime.AddCleanUp`.
* Added GOPJRT_TEXT_STABLE_HLO option to force XlaBuilder to use StableHlo text representation.
  * Use with `-vmodule=compile=2` to enable logging of each program compiled. 
* CUDA driver:
  * If the plugin is NVidia CUDA, set XLA_FLAGS=--xla_gpu_cuda_data_dir to the nvidia directory with drivers,
    if one was installed.
  * Updated `install_cuda.sh` script to create a nvidia/bin directory and link the downloaded `cuda_nvcc/bin/ptxas` there. 
* Removed reference to `xla_data` (or any other) protos from the public API.

Merge pull request #36 from gomlx/xla

v0.7.0: Updated XLA, bumped version, plugin owned arenas.

Bumped version.

Updated coverage.

Merge pull request #30 from gomlx/v062

Updated C/C++ wrapper version number.

Merge pull request #29 from gomlx/v061

V061

Merge pull request #24 from gomlx/bitwise

v0.6.0: Bitwise operators & C/C++ wrappers version check

Merge pull request #23 from gomlx/xla

v0.5.1 Sync'ed XLA; Added shift operators