- SoundBuffer.gain(factor): new DSP method for amplitude scaling before
mixing (0.5 = half volume, 2.0 = double, clamped to int16 range)
- Fix sfxr square/saw waveform artifacts: phase now wraps at period
boundary instead of growing unbounded; noise buffer refreshes per period
- Fix PySound construction from SoundBuffer on SDL2 backend: use
loadFromSamples() directly instead of copy-assign (deleted on SDL2)
- Add Image::create(w, h, pixels) overload to HeadlessTypes and
SDL2Types for pixel data initialization
- Waveform test suite (62 lines)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
