V66 FIX STRIKE-PARALLEL AXIS SCALE

Base
- Starts from V65.

What was wrong
- V65 misinterpreted the requested "1.4x fault strike length" for the side-petal strike-parallel axis.
- It applied 1.4x to the Gaussian sigma itself, which made the visible total axis much too long (around several times the intended span).

What changed
- The remaining same-sign side petal keeps the V65 logic, but its strike-parallel sigma is reduced from 1.40 * half_len to 0.70 * half_len.
- This makes the visible full strike-parallel axis roughly 1.4x the fault strike length, instead of around 4x.

Other V65 settings preserved
- End petals moved 3.5x outward
- Opposite same-sign side petal removed
- Remaining side petal outward axis kept at 0.5x
- Coast fix from V64 preserved
