- SEARCH_ORBITS increased from 5 to 10
- Added last_scan_end tracking: when sim_time passes the end of the
current scan window with no crossing pending, automatically rescans
the next SEARCH_ORBITS ahead
- Title bar now shows 'rescan in Xs' instead of just 'No upcoming SOI
crossing', making the system's state visible
- Fixes bug #3: asteroid entering SOI undetected because the scan
window had expired
After SOI exit the asteroid has new orbital elements (gravity assist).
Previously the old trail and crossing predictions were never updated,
causing three bugs:
1. Old trajectory still drawn after exit
2. Next SOI entry time based on stale orbit
3. Subsequent SOI entries never triggered
Now on exit: recompute trail, rescans for future SOI crossings,
and resets the crossing index.
