feat: add PortAudio device enumeration utility

- Created script to list all available audio input/output devices with their capabilities
- Displays host APIs, channel counts, sample rates, and device names for configuration
- Includes helpful hints for selecting appropriate capture and playback devices

list_portaudio_devices.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+import sys
+try:
+    import sounddevice as sd
+except Exception as e:
+    sys.stderr.write("sounddevice is not installed or failed to import. Install with: pip install sounddevice\n")
+    raise
+
+ha = sd.query_hostapis()
+print("Host APIs:")
+for i, h in enumerate(ha):
+    print(f"{i}: {h.get('name')}")
+
+print("\nDevices:")
+for i, d in enumerate(sd.query_devices()):
+    api_idx = d.get('hostapi')
+    api = ha[api_idx].get('name') if isinstance(api_idx, int) and 0 <= api_idx < len(ha) else '?'
+    name = d.get('name')
+    mi = int(d.get('max_input_channels') or 0)
+    mo = int(d.get('max_output_channels') or 0)
+    sr = int(d.get('default_samplerate') or 0)
+    print(f"{i:2d} | in={mi:<2d} out={mo:<2d} sr={sr:<6d} api={api} name={name}")
+
+print("\nHints:")
+print("- Pick an INPUT index with in>0 that matches your capture device name (e.g., 'USB Audio Device').")
+print("- Pick an OUTPUT index with out>0 that matches your playback device name (e.g., 'USB Audio').")
+print("- We will use mono (channels=1). If mono fails, we can fall back to 2 channels.")