* fix: auto-detect audio sample rate for device compatibility (#262)
- Add _get_supported_sample_rate() helper function
- Tests device default rate first, then common rates (48k, 44.1k, 32k, 22k, 16k, 8k)
- Fixes 'Invalid sample rate' error for devices like Vocaster One (48kHz only)
- Update test_audio_input(), _record_audio(), and _attempt_audio_reconnection()
- Return detected sample_rate in test_audio_input() result dict
* fix: import pyaudio inside _get_supported_sample_rate
* fix: resample audio to 16kHz for Vosk/Whisper compatibility
- Store detected sample rate in self._capture_sample_rate
- Resample audio chunks to 16kHz before appending to buffer (linear interpolation)
- Initialize _capture_sample_rate to 16000 in __init__
- Update both _record_audio() and _attempt_audio_reconnection()
This ensures devices like Vocaster One (48kHz only) can capture audio
and speech recognition engines (Vosk/Whisper) receive 16kHz as expected.
* style: fix black formatting
* feat(ui): show sample rate info in audio test results
- Display detected sample rate in test results (e.g., '48kHz → 16kHz auto')
- Remove redundant numpy import in _record_audio function
- Helps users understand that non-16kHz devices are supported
