feat: separate column layout for Recent QSOs in the Main tab

The Main-tab pane and the full Recent QSOs tab are the same component sharing
one storage key, but the pane is about half as wide — so it wants fewer and
narrower columns. Whichever was opened last rewrote the other's widths.

The pane now stores under "mainpane", which also scopes its award-column
visibility and widths. The full tab keeps the historical key, so its layout is
untouched; the pane starts from defaults once.

changelog.json

@@ -4,10 +4,12 @@
     "date": "2026-07-27",
     "en": [
       "Column layouts (widths, order, hidden columns) now stick — five faults were undoing them.",
+      "Recent QSOs keeps a separate column layout in the Main tab and in its own tab — the pane is half as wide there.",
       "ACOM and SPE amplifiers can follow OpsLog's frequency, on a second COM port (Settings → Amplifier)."
     ],
     "fr": [
       "Les dispositions de colonnes (largeurs, ordre, colonnes masquées) tiennent enfin — cinq défauts les défaisaient.",
+      "Les QSO récents gardent une disposition de colonnes distincte dans l'onglet Principal et dans leur propre onglet — le volet y est deux fois moins large.",
       "Les amplificateurs ACOM et SPE peuvent suivre la fréquence d'OpsLog, sur un second port COM (Réglages → Amplificateur)."
     ]
   },

frontend/src/App.tsx

@@ -4200,6 +4200,11 @@ export default function App() {
           <div className="h-full w-full min-h-0 flex flex-col bg-card border border-border rounded-lg overflow-hidden">
             <RecentQSOsGrid
               key={`rqg-${activeProfileId ?? 'x'}`}
+              // Its OWN layout, separate from the full-width Recent QSOs tab.
+              // This pane is roughly half as wide, so it wants fewer columns and
+              // narrower ones; sharing one key meant whichever was opened last
+              // rewrote the other's widths.
+              storageKey="mainpane"
               rows={qsosWithAwards as any}
               myGrid={station.my_grid}
               total={total}