Feature: Remember the last-used signal between games (#9792)

src/table/settings/gui_settings.ini

@@ -458,6 +458,14 @@ strval   = STR_CONFIG_SETTING_SIGNAL_GUI_MODE_PATH
 post_cb  = [](auto) { CloseWindowByClass(WC_BUILD_SIGNAL); }
 cat      = SC_ADVANCED
 
+[SDTC_VAR]
+var      = gui.default_signal_type
+type     = SLE_UINT8
+flags    = SF_NOT_IN_SAVE | SF_NO_NETWORK_SYNC
+def      = 5
+min      = 0
+max      = 5
+
 [SDTC_VAR]
 var      = gui.coloured_news_year
 type     = SLE_INT32