whisperx has no upstream AMD GPU support and its core transcription path
(faster-whisper -> ctranslate2) falls back to CPU on AMD since the PyPI
ctranslate2 is CUDA-only. The torch rocm wheels would accelerate only the
alignment/diarization stages, producing a misleadingly half-working image.
Drop the hipblas variant rather than shipping a partially accelerated build
users can't distinguish from the real thing. AMD hosts now fall through
the capability map to cpu-whisperx / cpu-whisperx-development.
Also removes the now-dangling rocm-whisperx assertion from
pkg/system/capabilities_test.go and the ROCm mention from the whisperx
row in docs/content/reference/compatibility-table.md.
Assisted-by: Claude Code:claude-opus-4-7
Container images that install CUDA runtime libraries (e.g., cuda-cudart-12-5
via apt) create /usr/local/cuda-12 directories as a side effect. The previous
code checked for these directories before checking whether a GPU was present,
causing CPU-only hosts to select a CUDA backend that crashes because
libcuda.so.1 is absent.
Reorder checks so CUDA directory existence only refines the capability when
an NVIDIA GPU is actually detected, consistent with the arm64 L4T code path.
Signed-off-by: Sertac Ozercan <sozercan@gmail.com>
