feat: Yaesu control panel (meters, bands, DSP, TX), and drop a stale Flex hint

A console pane for the native Yaesu backend, in the same shape as the Icom and
Flex ones: S/PO/SWR meters, band and mode rows, AF/RF/squelch, AGC, the IPO/AMP1/
AMP2 front-end selector, ATT, NB, DNR + level, narrow filter, power in watts, mic
gain, VOX, split and ATU tune.

Three decisions worth keeping:

Panel reads are STAGGERED and live in their own file, away from ReadState. Meters
poll every cycle; settings only change when someone turns a knob, so they refresh
every 8th cycle and right after any set. Polling all of it every cycle would put
twenty queries a second on the serial link the frequency display shares.

Band buttons use the rig's own band memory (BS) rather than a frequency we pick,
so 20 m lands where the operator last was on 20 m — what the radio's own band
keys do.

A set is followed by a read-back, so the panel shows what the RIG ended up with,
not what we asked for; the two differ whenever a value is out of range or the
mode forbids the control. And a control the model lacks keeps its previous value
instead of dropping to zero, which reads as a setting that reset itself.

The S9 point of the S-meter scale is a hypothesis (the manual does not state it)
and is commented as such — one number to correct if reports come out an S unit
off, rather than a fudge spread through the RST helper.

Also removes the FlexRadio settings blurb, which explained the backend to
someone who had already chosen it.

frontend/wailsjs/go/main/App.d.ts

@@ -499,6 +499,8 @@ export function GetWinkeyerSettings():Promise<main.WinkeyerSettings>;
 
 export function GetWinkeyerStatus():Promise<winkeyer.Status>;
 
+export function GetYaesuState():Promise<cat.YaesuTXState>;
+
 export function HasBuiltinReferences(arg1:string):Promise<boolean>;
 
 export function IcomRefresh():Promise<void>;
@@ -755,6 +757,8 @@ export function RefreshCtyDat():Promise<main.CtyDatInfo>;
 
 export function RefreshSolar():Promise<void>;
 
+export function RefreshYaesuPanel():Promise<void>;
+
 export function ReloadUDPIntegrations():Promise<Array<string>>;
 
 export function RemovePassphrase(arg1:string):Promise<void>;
@@ -911,6 +915,36 @@ export function SetUltrabeamDirection(arg1:number):Promise<void>;
 
 export function SetWinkeyerTrace(arg1:boolean):Promise<void>;
 
+export function SetYaesuAFGain(arg1:number):Promise<void>;
+
+export function SetYaesuAGC(arg1:string):Promise<void>;
+
+export function SetYaesuAtt(arg1:number):Promise<void>;
+
+export function SetYaesuBand(arg1:string):Promise<void>;
+
+export function SetYaesuMicGain(arg1:number):Promise<void>;
+
+export function SetYaesuNB(arg1:boolean):Promise<void>;
+
+export function SetYaesuNR(arg1:boolean):Promise<void>;
+
+export function SetYaesuNRLevel(arg1:number):Promise<void>;
+
+export function SetYaesuNarrow(arg1:boolean):Promise<void>;
+
+export function SetYaesuPower(arg1:number):Promise<void>;
+
+export function SetYaesuPreamp(arg1:number):Promise<void>;
+
+export function SetYaesuRFGain(arg1:number):Promise<void>;
+
+export function SetYaesuSplit(arg1:boolean):Promise<void>;
+
+export function SetYaesuSquelch(arg1:number):Promise<void>;
+
+export function SetYaesuVOX(arg1:boolean):Promise<void>;
+
 export function StartCWDecoder():Promise<void>;
 
 export function StationSetRelay(arg1:string,arg2:number,arg3:boolean):Promise<void>;
@@ -947,6 +981,8 @@ export function TestStationDevice(arg1:main.StationDevice):Promise<main.StationT
 
 export function TestUltrabeam(arg1:main.UltrabeamSettings):Promise<void>;
 
+export function TuneYaesuATU():Promise<void>;
+
 export function TunerGeniusActivate(arg1:number):Promise<void>;
 
 export function TunerGeniusAutotune():Promise<void>;