fix(elecraft): MOX would not unkey, and the TX meters never moved

Both are the same bug. ReadState returns early while transmitting — the
rig answers '?;' to IF; then, and treating that as a fault used to drop
the link — but that early return also skipped the panel update and the
meter read.

So the panel believed the radio was still receiving. Pressing MOX again
therefore sent ANOTHER transmit command instead of RX, and the K3 stayed
keyed, exactly as reported. And the power and SWR bars were only ever
read at the one moment they mean nothing.

Reading meters while transmitting needs one more guard: a '?;' then says
when the question was asked, not what the radio supports, so the
unsupported-command memory is suspended for that read. Without it, one
badly timed refusal would silence a meter for the rest of the session.

Adds RIT/XIT offset control (±10/±100 Hz, offset shown), a 4.0 kHz filter
button for FT8, and logs the K3's icon word when it changes: there is no
command for 'is the ATU in line', the reference says the switch functions
show up as icon changes, so an operator toggling the ATU while watching
the log will name the bit and the button can then light up honestly.

frontend/wailsjs/go/models.ts

@@ -1094,6 +1094,7 @@ export namespace cat {
 	    antenna: number;
 	    rit: boolean;
 	    xit: boolean;
+	    rit_offset: number;
 	    key_speed: number;
 	    meters_provisional: boolean;
 	
@@ -1129,6 +1130,7 @@ export namespace cat {
 	        this.antenna = source["antenna"];
 	        this.rit = source["rit"];
 	        this.xit = source["xit"];
+	        this.rit_offset = source["rit_offset"];
 	        this.key_speed = source["key_speed"];
 	        this.meters_provisional = source["meters_provisional"];
 	    }