feat: a typed watering hole carries its mode; Yaesu RTTY sideband

His log settles the 28.074 case: "SetCATFrequency 28.074 MHz" and the
state still reads mode=USB — nothing sent a mode, so the rig simply
stayed where it was. A spot click has always carried one; a frequency
typed by hand carried none. It now uses the same table and the same
tolerance as a spot (±3 kHz of a known FT8/FT4/JS8 frequency), and only
towards the digital modes: tuning AWAY from one leaves the mode alone,
because there the frequency says nothing about what the operator means.

RTTY on Yaesu is a choice the log cannot make: ADIF records "RTTY" and
the rig has MD06 (RTTY-L) and MD09 (RTTY-U). The older lower sideband
stays the default and a station whose FSK controller wants the upper one
says so once in Settings → CAT.

frontend/wailsjs/go/models.ts

@@ -2379,6 +2379,7 @@ export namespace main {
 	    kenwood_baud: number;
 	    kenwood_data_mode: string;
 	    yaesu_low_lines: boolean;
+	    yaesu_rtty_usb: boolean;
 	    kenwood_low_lines: boolean;
 	    icom_port: string;
 	    icom_baud: number;
@@ -2432,6 +2433,7 @@ export namespace main {
 	        this.kenwood_baud = source["kenwood_baud"];
 	        this.kenwood_data_mode = source["kenwood_data_mode"];
 	        this.yaesu_low_lines = source["yaesu_low_lines"];
+	        this.yaesu_rtty_usb = source["yaesu_rtty_usb"];
 	        this.kenwood_low_lines = source["kenwood_low_lines"];
 	        this.icom_port = source["icom_port"];
 	        this.icom_baud = source["icom_baud"];