Extend Mode constants (3=TCPServer, 4=UDPServer, 5=COMPort) with
explicit values. Refactor Target to support multiple connection types
(listener+conns map, packetConn, serialPort). Add acceptLoop,
readLoopPacket, readLoopSerial. Mode-aware Broadcast dispatches to
all accepted conns (TCP-S), known remotes (UDP-S), or serial port.
Update flag help, command completions, and TUI panel hints.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Replace complex ptrVal/Val/Flag type machinery with direct pflag
calls. Move flag logic and interactive wizard to internal/flag
package. Eliminate ~200 lines of flag boilerplate.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>