* fix(transcription): reject symlinked audio inputs
Validation runs before provider selection, so rejecting symbolic-link paths there prevents supported-extension links from being treated as normal audio files. Use os.path.islink to avoid perturbing the existing Path.stat error path and to reject links before resolving targets.
Constraint: Keep validation platform-safe and avoid requiring symlink support where unavailable.
Rejected: Use Path.is_symlink | it consumes pathlib stat calls and broke the existing stat error regression.
Confidence: high
Scope-risk: narrow
Directive: Keep path hardening in _validate_audio_file before provider dispatch.
Tested: source venv/bin/activate && python -m pytest tests/tools/test_transcription_tools.py::TestValidateAudioFileEdgeCases -q (5 passed)
Tested: source venv/bin/activate && python -m pytest tests/tools/test_transcription_tools.py::TestValidateAudioFileEdgeCases tests/tools/test_transcription_tools.py::TestTranscribeAudioDispatch::test_invalid_file_short_circuits -q (6 passed)
Tested: source venv/bin/activate && python -m compileall tools/transcription_tools.py tests/tools/test_transcription_tools.py
Tested: git diff --check
Not-tested: Full tests/tools/test_transcription_tools.py under .[dev] only; existing faster_whisper optional dependency tests fail with ModuleNotFoundError.
* Keep transcription tests independent of optional whisper install
The transcription suite mocks faster-whisper directly, so a minimal test stub keeps the branch verifiable in environments where the optional package is not installed. This preserves the existing mock-based coverage without adding a dependency.
Constraint: faster-whisper is an optional local STT dependency and is absent from the current validation environment
Rejected: Install faster-whisper just for branch validation | would add heavyweight environment coupling outside the patch scope
Confidence: high
Scope-risk: narrow
Directive: Keep this as a test-only stub unless production import semantics change
Tested: pytest tests/tools/test_transcription_tools.py -q
---------
Co-authored-by: WuKongAI-CMU <210765158+WuKongAI-CMU@users.noreply.github.com>