Summary

• add built-in GPU and VRAM status modules
• document both modules and add test coverage

Why

Catppuccin tmux already exposes CPU and RAM modules via tmux-cpu, but it does not provide built-in modules for GPU utilization or GPU memory usage.
This is especially useful for local AI workloads, where CPU and system RAM alone are often not enough to understand actual system pressure.

Notes

• the GPU module uses tmux-cpu's gpu_* placeholders
• the VRAM module is user-facing as vram, and uses tmux-cpu's gram_* placeholders internally

Testing

• SOCKET_NAME=tmuxforkgpu bash tests/harness.sh --test tests/gpu_module.sh --expected tests/gpu_module_expected.txt
• SOCKET_NAME=tmuxvramcheck bash tests/harness.sh --test tests/vram_module.sh --expected tests/vram_module_expected.txt
• SOCKET_NAME=tmuxvramfullcheck bash run_tests.sh