fix(stt): fall back on CUBLAS_STATUS_NOT_SUPPORTED

[liuhao1024]

What does this PR do?

• Treat CUBLAS_STATUS_NOT_SUPPORTED as a CUDA library/runtime error in local STT.
• Add regression coverage for Blackwell/faster-whisper failures falling back to CPU.

Related Issue

N/A

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Changes Made

• See commit messages for detailed changes

How to Test

1. Run pytest tests/ -q — all tests should pass
2. Verify the specific scenario described above is resolved

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: macOS 26.4.1

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture and workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A

[teknium1]

Thanks for the focused regression fix. Current main still leaves CUBLAS_STATUS_NOT_SUPPORTED out of _CUDA_LIB_ERROR_MARKERS (tools/transcription_tools.py:1065-1086), so the existing runtime fallback re-raises this exact Blackwell error at tools/transcription_tools.py:1141-1163 instead of retrying on CPU.

The diff adds the exact missing classifier value and tests the existing cached-model eviction and CPU-int8 retry path. The implementation is narrowly scoped, matches the existing fallback design introduced in 4350668ae, and does not add configuration or tool surface.

Automated hermes-sweeper review.

[teknium1]

Merged into main via consolidated salvage PR #73510 (merge c0c5dac531). Your CUBLAS_STATUS_NOT_SUPPORTED marker addition (Blackwell/RTX-5090 CPU fallback) was cherry-picked with your authorship and sabotage-verified by its regression test.

Your contribution is credited to you in git history. Thank you! Closing this PR as merged-via-salvage.