fix: blank ADIF monitor settings panel (hooks in a called-as-function panel)

PANELS[selected]() invokes each settings panel as a plain function, so a panel
must not call hooks. ADIFMonitorPanel uses useState/useEffect/useI18n, which
broke the Rules of Hooks and blanked the section. Render it through JSX
(() => <ADIFMonitorPanel />) so it mounts as a real component with its own
hook context — same pattern as the Flex panel.

frontend/src/components/SettingsModal.tsx

@@ -4511,7 +4511,10 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
     'lists-modes':  ModesPanel,
     cluster:        ClusterPanel,
     udp:            UDPIntegrationsPanelWrapper,
-    adifmon:        ADIFMonitorPanel,
+    // Rendered as a real element (not called as a bare function) so its own hooks
+    // — useState/useEffect/useI18n — get a proper component context; PANELS[x]()
+    // is a plain call and hook-holding panels must go through JSX like this.
+    adifmon:        () => <ADIFMonitorPanel />,
     backup:         BackupPanel,
     database:       DatabasePanel,
     uscounties:     USCountiesPanel,