The _test.py files in cuda_bindings/examples/ are run under pytest,
so sys.exit(1) for unsupported configurations causes SystemExit(1)
which pytest treats as a test failure. Use pytest.skip() instead for
platform/device/capability checks that indicate unsupported configs.
Actual test failures (incorrect results) still use sys.exit(1).

Made-with: Cursor

Apply consistent variable names for common objects across all
cuda.core example files, addressing issue NVIDIA#1675.

Conventions applied:
- Stream: `stream` (not `s`), numbered `stream0`/`stream1`
- Kernel: `kernel` (not `ker`/`gpu_ker`), descriptive `add_kernel`/`sub_kernel`
- Program: `prog` (not `gpu_prog`)
- Kernel args: `kernel_args` (not `ker_args`)
- Program options: `program_options` (not `opts`), using ProgramOptions (not dicts)
- Grid/block: `grid`/`block` (not `grid_size`/`block_size`)

Made-with: Cursor

- Remove success/completion fluff messages ("done!", "passed", etc.)
- Use sys.exit(1) instead of sys.exit(0) for unsupported configurations
- Send skip/warning/error messages to stderr
- Replace user-facing assert with proper checks
- Standardize sys.exit(-1) to sys.exit(1)

Made-with: Cursor

The _test.py files in cuda_bindings/examples/ are run under pytest,
so sys.exit(1) for unsupported configurations causes SystemExit(1)
which pytest treats as a test failure. Use pytest.skip() instead for
platform/device/capability checks that indicate unsupported configs.
Actual test failures (incorrect results) still use sys.exit(1).

Made-with: Cursor

Add the blank-line separation required by Ruff so pre-commit.ci can complete successfully on this branch.

Made-with: Cursor

…rror

Move GPU/example-only runtime dependencies into a dedicated `examples` pixi environment so the test environment stays lean, and clarify gl_interop_plasma import failures by reporting the underlying OpenGL import error instead of a generic pyglet version message.

Made-with: Cursor