Clip out-of-range audio before the voice activity check - #101

trim_long_silences packs the waveform as 16-bit samples for the voice activity check. A sample of 1.5 came back as -16386, and -1.5 came back as 16386. The values wrap past the 16-bit range, so the check hears a different signal.

Out-of-range samples are clipped. 1.5 stays 32767. -1.5 stays -32767. 1.0, -1.0, and 0.0 stay 32767, -32767, and 0.

Test plan

• test_out_of_range_samples_do_not_wrap is red on the old cast (1.5 is -16386) and green after the clip
• In-range samples 1.0, -1.0, and 0.0 are unchanged