Function save_wav_mono_i16 

pub fn save_wav_mono_i16(
    path: &Path,
    samples: &[f32],
    sample_rate: u32,
) -> Result<(), Box<dyn Error>>

Saves mono PCM samples to a 16-bit WAV file.

Parameters:

• path: destination WAV path.
• samples: normalized mono samples (typically in [-1, 1]).
• sample_rate: sample rate in Hz. Returns:
• Result<(), Box<dyn Error>>: Ok(()) on success.