V68 TEMPORARY PETAL TUNING SLIDERS

Base
- Starts from V67.
- Keeps the coast fix from V64 and the restored opposite petal / lengthened end petals from V67.

New temporary UI
- Settings window now has a new Petal tab.
- The Petal tab has horizontal scrollbar sliders for:
  1. Main outward axis
  2. Main strike full axis
  3. Opposite petal length
  4. End outward offset
  5. End strike length
- Press Regenerate secondary now in that tab, or press G in stamp mode, to rebuild auto secondary deformation using the current slider values.
- Reset petal defaults restores the V67 values.

Purpose
- This is intended as a temporary manual tuning interface so the clover / teardrop deformation geometry can be adjusted interactively before hard-coding final values.
