TSSIM/JESIM final v42 - finite-fault stamp aspect-ratio width scaling

Base: v41 fault stamp delay build.

Change:
- In finite-fault stamp mode, changing stamp width now scales stamp length at the same time.
- This keeps the current stamp rectangle aspect ratio instead of changing only the width.
- < / > in stamp mode adjust width + length together.
- The Settings width +/- buttons also scale stamp length when stamp mode is active.
- Directly applying a new Fault width (km) value while stamp mode is active also keeps the current stamp length/width ratio.

Behavior:
- If an open fault group is active, < / > changes that open fault group's future stamp size.
- If no open fault group is active, < / > changes the next new fault's stamp size.
- J / K still changes stamp length only, so you can intentionally set the aspect ratio before scaling the whole stamp with < / >.

Unchanged from v41:
- S stamp mode, N/Enter complete fault, Tab cycle, Z/X strike, [/] delay.
- Adjacent stamp bridging.
- Advanced node tuning and multi-select.
- Fault width is true down-dip width in km.
- JESIM 5-minute arrived-station updates and packet_meaningful_update.
- Shimizu removed, no axis flip, external wall-clock 1x, transmit-only 60h cap.
