Context

FlexRadio shipped FlexLib v4.2.18.41174 today. The VITA discovery beacon adds two new fields. Small additive parse update for RadioDiscovery.

Reference: ~/build/FlexLib/FlexLib/Discovery.cs (line 243 + 370) and Vita/VitaDiscovery.cs.

What the radio broadcasts now

• is_system_model=<0|1> — flags bench / system-build radios. Stored as Radio.IsSystemModel in FlexLib.
• turf_region=<string> — turf region indicator distinct from the existing region= field. Stored as Radio.TurfRegion.

Work for AetherSDR

• Parse both fields in RadioDiscovery::onDiscoveryPacket (or whichever entry parses the beacon).
• Surface them in RadioInfo so the connect dialog can display / sort by them.
• Confirm the existing parser doesn't trip on unknown keys before this lands (regression check).

Trivial scope — single-PR work. Just additive parsing.