Vibrato (LFO frequency modulation):
- New VibratoSpec in SoundSpec: rate (Hz), depth (cents), delay (s)
- ChannelRenderer applies vibrato to frequency each tick
- Supported on Pulse and Triangle channels
- GUI: vibrato controls (enable, rate, depth) in channel panel
- Enables bird chirps, sirens, wobbles
Feedback loop fixes:
- generate_batch now accepts full SoundSpec array (not just names)
so each sound is unique
- render_sound returns reference examples from feedback DB
- Fixed GUI bug: clicking stars no longer erases feedback text
- Feedback text auto-saves on Enter / focus loss
- Replaced emoji buttons (✓/🗑) with text (Save/Del)
- Green saved indicator when feedback exists in DB
99 tests passing, 0 warnings
Emil
58c47fe286