Extend the rotctld wire protocol with three new commands that enable
signal strength measurement through the Carryout G2's DVB subsystem:
- R [n]: Read RSSI (handles motor→dvb→rssi→motor menu dance internally)
- L: Enable LNA for signal reception (one-time pre-scan setup)
- D: Discover capabilities (returns CAPS:rssi,lna for G2, empty for others)
Non-G2 protocols return RPRT -6 (not available) for R and L commands.
The menu state invariant is maintained after every operation so P commands
continue to work between RSSI reads.
Ryan Malloy
1192b31166