flatudp: the signal-list codec, with a hand-computed decode check

src/ui_app.hpp

@@ -1883,6 +1883,9 @@ gboolean e1608_probe(gpointer user);
 gboolean e1608_probe_report(gpointer user);
 gboolean e1608_probe_reconnect(gpointer user);
 gboolean e1608_probe_resumed(gpointer user);
+/// The flat UDP (MARTe2 UDPSender) source: the signal-list codec and a hand-computed decode, then,
+/// against `tools/mock_flatudp.py`, the stream, the wrong-size accounting and the silence timeout.
+gboolean flatudp_probe(gpointer user);
 gboolean pan_probe(gpointer user);
 gboolean arm_probe(gpointer user);
 gboolean trigrenum_probe_step3(gpointer user);