feat(lookup): optional QRZ nickname as the logged name

QRZ publishes <nickname> — the name an operator goes BY on the air — and
OpsLog was composing fname + name instead. "Bob" is what belongs in a log;
"Robert J Smith" is what belongs on a licence.

QRZ only, and deliberately so: HamQTH's <nick> already fills the Name field
that way, so the same switch there would toggle a behaviour it has no way to
turn off.

A published nickname is optional, so an empty one falls through to the
registered name. That is the whole point of it being a fallback rather than a
swap, and it is what the test pins — a blank nickname must never blank the
name.

frontend/src/components/SettingsModal.tsx

@@ -1224,6 +1224,7 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
     hamqth_user: '', hamqth_password: '',
     primary: '', failsafe: '',
     download_images: false,
+    qrz_prefer_nickname: false,
     cache_ttl_days: 30,
   });
   // Per-provider Test state — keeps the success/error feedback adjacent
@@ -2312,6 +2313,23 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
               </span>
             </span>
           </label>
+
+          {/* QRZ only. HamQTH's <nick> already fills the Name field with the
+              on-air name, so the same switch there would toggle a behaviour it
+              has no way to turn off. */}
+          <label className="flex items-start gap-2 text-sm cursor-pointer mt-3">
+            <Checkbox
+              checked={!!(lookup as any).qrz_prefer_nickname}
+              onCheckedChange={(c) => setLookup((s) => ({ ...s, qrz_prefer_nickname: !!c } as any))}
+              className="mt-0.5"
+            />
+            <span>
+              {t('lk.qrzNickname')}
+              <span className="block text-xs text-muted-foreground mt-0.5">
+                {t('lk.qrzNicknameHint')}
+              </span>
+            </span>
+          </label>
         </div>
 
         <div className="mt-6 pt-4 border-t border-border">