- Add TestGroupFieldPopulated test to verify all ClassFreqConfigs have non-empty Group (GRP-01)
- Change TestHarmonicsNonEmpty threshold from < 2 to < 1 (accepts single-harmonic sine entries)
- Fix oscillator Advance() to use math.Abs(h.Amplitude) for normalization weight accumulation:
triangle wave uses alternating-sign amplitudes; signed sum underestimates totalWeight causing
output to exceed [-1,1] bounds when using WaveformPresetHarmonics (Rule 1 bug fix)
- Update TestStereoPan to use ClassSSH (pan=-0.7) instead of ClassDHCP (pan changed to 0.1)
- Update TestNewBankCustomConfigNoClip: passes after oscillator normalization fix
- Fix TestLoadPartialOverrideFrequency: derive expected WaveformType from defaults (not hardcoded 0)
- Fix TestAutoFreqSkipsBuiltins: derive expected HTTPS BaseHz from defaults (150.0 in Phase 9)