Round 1 findings and fixes, all previously uncommitted:
- FXProcessor per-slot DSP history repair (HEAD does not compile without it)
- SynthVoice::getModulationValue, editor control-lock guard
- ExactCompare.h naming the deliberate exact float comparisons
- KnobLookAndFeel replacing the never-installed SerumLookAndFeel
- 55 first-party compiler warnings to 0
- AGENT.md renamed to AGENTS.md across Source/
- graft repository context graph and its hooks
- JANITOR_TASKS.md and UI_UX_AUDIT.md records
Add Oscillator::setParams() which updates detune, pan, and gain for
already-initialised sub-voices without resetting their phases. This
preserves phase continuity when unison or spread is LFO-modulated at
control rate. noteOn() now just seeds phases and delegates to
setParams().
Precompute panL/panR in SubVoice instead of calling cos/sin per
sample. Add paramsValid and cachedParams to skip redundant work.
Replace SynthVoice's lastUnisonA/B tracking with a single
oscillatorsNeedNoteOn flag: noteOn sets it, render clears it after
the first block. Add SubLevel and NoiseLevel to the per-voice
modulation targets so they can be modulated like other parameters.