fix(panels): the wheel moved whatever slider the pointer was over

The rig-panel sliders take a non-passive wheel listener and acted on
hover, so scrolling the panel fed the gesture to whichever control sat
under the cursor — RF power included, mid-QSO. An operator scrolling to
read the bottom of the panel could change his transmit power without
touching anything.

They now require focus, i.e. a deliberate click on that slider first.
Without it the event is left alone and the panel scrolls, which is what
the operator meant. Same fix on the Flex and Yaesu panels, which share
the pattern.

This is a fault in its own right. It is NOT an explanation for the
"transmit power moves since 0.22.8" report: that release changed nothing
in the Icom path, and this behaviour is older than it.

frontend/src/components/FlexPanel.tsx

@@ -86,6 +86,13 @@ function Slider({ value, onChange, disabled, accent = '#16a34a', step = 1, max =
     if (!el) return;
     const onWheel = (e: WheelEvent) => {
       if (disRef.current) return;
+      // The wheel only acts on a slider the operator has DELIBERATELY taken
+      // hold of — one that has focus. Hovering was enough before, so scrolling
+      // the panel with the pointer anywhere over these controls silently moved
+      // whatever sat under it: an IC-7800 owner watched his transmit power
+      // change on its own. Without focus the event is left alone and the panel
+      // scrolls, which is what the gesture was for.
+      if (document.activeElement !== el) return;
       e.preventDefault();
       const d = e.deltaY < 0 ? stepRef.current : -stepRef.current;
       const nv = Math.max(0, Math.min(maxRef.current, valRef.current + d));

frontend/src/components/IcomPanel.tsx

@@ -125,6 +125,13 @@ function Slider({ value, onChange, disabled, accent = '#2563eb', step = 1 }: {
     if (!el) return;
     const onWheel = (e: WheelEvent) => {
       if (disRef.current) return;
+      // The wheel only acts on a slider the operator has DELIBERATELY taken
+      // hold of — one that has focus. Hovering was enough before, so scrolling
+      // the panel with the pointer anywhere over these controls silently moved
+      // whatever sat under it: an IC-7800 owner watched his transmit power
+      // change on its own. Without focus the event is left alone and the panel
+      // scrolls, which is what the gesture was for.
+      if (document.activeElement !== el) return;
       e.preventDefault();
       const d = e.deltaY < 0 ? stepRef.current : -stepRef.current;
       const nv = Math.max(0, Math.min(100, valRef.current + d));

frontend/src/components/YaesuPanel.tsx

@@ -149,6 +149,13 @@ function Slider({ value, onChange, disabled, accent = 'var(--primary)', min = 0,
     if (!el) return;
     const onWheel = (e: WheelEvent) => {
       if (disRef.current) return;
+      // The wheel only acts on a slider the operator has DELIBERATELY taken
+      // hold of — one that has focus. Hovering was enough before, so scrolling
+      // the panel with the pointer anywhere over these controls silently moved
+      // whatever sat under it: an IC-7800 owner watched his transmit power
+      // change on its own. Without focus the event is left alone and the panel
+      // scrolls, which is what the gesture was for.
+      if (document.activeElement !== el) return;
       e.preventDefault();
       const nv = Math.max(minRef.current, Math.min(maxRef.current, valRef.current + (e.deltaY < 0 ? 1 : -1)));
       if (nv !== valRef.current) cbRef.current(nv);