Adds send_with_timeout() to CarryoutG2Protocol for long-running
commands, and az_sweep_firmware() to both SerialBridge and DemoDevice.
Sweep and Sky Map modes now try the firmware path first (single
azscanwxp command, streaming results) and fall back to software
step-dwell-measure on error or when "Software mode" checkbox is
checked. Software sweep fixed to set EL once and move AZ only.
F1 Position (compass rose, motor control, sparklines),
F2 Signal (RSSI gauge with sub-char precision, DVB/ADC sparklines, LNA toggle),
F3 Scan (AZ/EL grid sweep with heatmap and CSV export),
F4 System (NVS table, A3981 diagnostics, motor dynamics),
F5 Console (raw serial terminal with prompt detection and safety gates).
Includes SerialBridge (thread-safe protocol wrapper), DemoDevice
(synthetic simulation for --demo mode), dark RF theme with rounded
borders and teal accents, and send_raw() on CarryoutG2Protocol.
