V52 HALO-STYLE SECONDARY DEFORMATION

What changed
- Replaced the previous multi-lobe auto-secondary generator with a ribbon-attached halo field.
- Removed explicit tip settlement caps at both rupture ends.
- Removed the thin strike-parallel flank stripe / detached side shoulder behaviour.
- Secondary deformation is now generated mainly as a broad subsidence band just outside the down-dip edge of the continuous main-fault support.
- A much weaker uplift shoulder is still generated on the opposite side, but it is tied to the same ribbon and kept intentionally small.

Why
- For a very long rupture such as the 2011 Tohoku finite-fault model, the previous generator could create detached north/south blobs and a narrow side stripe that looked artificial.
- The observed pattern is better described as a light secondary deformation halo around the main deformation band.

Operational notes
- Press G to regenerate the automatic secondary deformation field after editing the finite-fault model.
- If the subsidence side appears flipped, use D to flip the generated subsidence side and regenerate again.

Implementation note
- This is still an empirical auto-secondary field, not a full elastic dislocation / Okada solution.
- The goal of V52 is to improve spatial shape realism for long, continuous ruptures.
