ui(stats): prettier slot drill-down + click a callsign to edit the QSO

The pop-up listing the QSOs behind a Stats band/mode square gets a cleaner header
(band chip, hint), banded/hover rows and roomier spacing. Callsigns are now
clickable and open the QSO editor (App.openEdit threaded through DetailsPanel →
BandSlotGrid → SlotQSOModal as onEditQso), matching the double-click-to-edit of
the log grids.

frontend/src/App.tsx

@@ -5653,6 +5653,7 @@ export default function App() {
             band={band}
             mode={mode}
             bands={bands}
+            onEditQso={openEdit}
             {...(!callsign.trim() && selQso ? {
               slotCall: selQso.call, slotBand: selQso.band, slotMode: selQso.mode,
               slotWb: selWb, slotWbBusy: selWbBusy,