DYN, ORTHO, POLAR, the polar increment, the grid toggle and the
object-snap configuration (OSNAP on/off, active snap modes, OTRACK)
reset to defaults on every launch. Persist them to a per-user
settings.txt, matching the existing recent-files / status-bar stores
(plain key=value, no serialization crate).
Settings load on boot and apply to live state; the update wrapper
snapshots them after each message and writes only on change, so a
toggle survives a restart without thrashing the file. LWT is left out
on purpose — it is a drawing header variable, not a UI preference.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
