- Split GalaxyParams into CoreParams, DiskParams, and BeamParams sub-structs
- Add polar beam systems (top/bottom) with visual differentiation
- Add scrollable control panel with section headers for each layer
- Fix Randomize Settings button: remove explicit width (use flex auto)
and bump height from 28px to 32px to match other action buttons
- Add mouse-wheel scroll routing for the control panel
- Add 'Randomize Settings' button that randomizes all params within bounds
- Add SystemOrigin enum for per-layer tracking
- Update AGENTS.md with new module layout and plugin pattern
francy51
f83a0c5e59