TSSIM / JESIM final v50 - fault-scale secondary deformation

Changes from v49:
- Automatic secondary deformation now scales from the whole fault_id envelope, not one stamp patch.
- The filled stamp ribbon is treated as one continuous finite fault before secondary deformation is generated.
- Main down-dip subsidence, finite-fault tip subsidence, and weak uplift shoulders use total rupture length and rupture area scaling.
- Single-stamp length is used only as a minimum scale so small faults still behave as before.

Kept from earlier versions:
- Stamp mode, nearest-stamp connection, plane-depth calculation, delay, undo, and aspect-preserving stamp size.
- JESIM 5-minute transmission with packet_meaningful_update.
- Shimizu observation removed.
- External wall-clock 1x observation transmit timing.
- No Y-axis flip.

Usage:
1. Unzip into a clean folder.
2. Run build_win_mingw.bat.
3. Run python jesim_ws_relay.py when using JESIM websocket output.

For existing v46/v49 presets:
- Load the preset normally.
- Secondary deformation is regenerated automatically.
- Press G in stamp mode to force regeneration if needed.
