fix: catch OSError on sounddevice import for CI without PortAudio

sounddevice raises OSError (not ImportError) when the PortAudio C
library is missing. This broke test collection on CI runners that
have the Python package installed but lack the native library.

tools/tts_tool.py

@@ -61,7 +61,7 @@ except ImportError:
 try:
     import sounddevice as sd
     _HAS_AUDIO = True
-except ImportError:
+except (ImportError, OSError):
     sd = None  # type: ignore[assignment]
     _HAS_AUDIO = False