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/src/App.tsx

@@ -73,6 +73,7 @@ import { BandMap } from '@/components/BandMap';
 import { WorldMap, LocatorMap } from '@/components/MainMap';
 import { FlexPanel } from '@/components/FlexPanel';
 import { IcomPanel } from '@/components/IcomPanel';
+import { YaesuPanel } from '@/components/YaesuPanel';
 import { AntGeniusPanel, type AGStatus } from '@/components/AntGeniusPanel';
 import { TunerGeniusPanel, type TGStatus } from '@/components/TunerGeniusPanel';
 import { ScpPanel, type ScpResult } from '@/components/ScpPanel';
@@ -1319,12 +1320,12 @@ export default function App() {
   // map ("map1"), the locator street map ("map2"), the cluster grid or the
   // worked-before grid. Per-profile (stored via SetUIPref → profile-prefixed),
   // so it's loaded async on mount and re-read on profile:changed below.
-  type MainPaneKind = 'map1' | 'map2' | 'cluster' | 'worked' | 'flex' | 'recent' | 'icom' | 'netcontrol';
+  type MainPaneKind = 'map1' | 'map2' | 'cluster' | 'worked' | 'flex' | 'recent' | 'icom' | 'yaesu' | 'netcontrol';
   const [mapZoomSignal, setMapZoomSignal] = useState(0); // bump → world map auto-zooms now
   const [mainPaneLeft, setMainPaneLeft] = useState<MainPaneKind>('map1');
   const [mainPaneRight, setMainPaneRight] = useState<MainPaneKind>('map2');
   const loadMainPanes = useCallback(async () => {
-    const valid = (v: string): v is MainPaneKind => v === 'map1' || v === 'map2' || v === 'cluster' || v === 'worked' || v === 'flex' || v === 'recent' || v === 'icom' || v === 'netcontrol';
+    const valid = (v: string): v is MainPaneKind => v === 'map1' || v === 'map2' || v === 'cluster' || v === 'worked' || v === 'flex' || v === 'recent' || v === 'icom' || v === 'yaesu' || v === 'netcontrol';
     const [l, r] = await Promise.all([
       GetUIPref('mainPaneLeft').catch(() => ''),
       GetUIPref('mainPaneRight').catch(() => ''),
@@ -4279,6 +4280,12 @@ export default function App() {
               onReportRST={(r) => { setRstSent(r); rstUserEditedRef.current = true; }} />
           </div>
         );
+      case 'yaesu':
+        return (
+          <div className="h-full w-full min-h-0 rounded-lg overflow-hidden border border-border">
+            <YaesuPanel onReportRST={(r) => { setRstSent(r); rstUserEditedRef.current = true; }} />
+          </div>
+        );
       case 'icom':
         return (
           <div className="h-full w-full min-h-0 rounded-lg overflow-hidden border border-border">
@@ -6074,6 +6081,7 @@ export default function App() {
           onMainPaneChanged={(side, v) => { if (side === 'left') setMainPaneLeft(v as MainPaneKind); else setMainPaneRight(v as MainPaneKind); }}
           flexAvailable={catState.backend === 'flex'}
           icomAvailable={catState.backend === 'icom'}
+          yaesuAvailable={catState.backend === 'yaesu'}
         />
       )}