feat(qsl): OpsLog QSL received marker + PSE/TNX card stamp + default QSL message

Received flag: new APP_OPSLOG_QSL_RCVD extra, toggled on the QSO edit window
next to QSL Message (immediate targeted write via SetOpsLogQSLReceived so it sets
AND clears reliably), plus a live PSE QSL / TNX indicator and a Recent-QSOs
column mirroring the sent one.

PSE/TNX card stamp: automatic — received → TNX, otherwise PSE QSL — exposed as
the {qso.pse_tnx} token (added to qslVars, so preview and send agree) and placed
in the default QSO-box footer; it can be moved to its own element in the designer.

Default QSL message: new qsl.default_message (QSLEmailTemplates.DefaultMessage),
edited under Settings → E-mail → QSL card e-mail. qslVars falls back to it when
the QSO's own QSLMSG is empty, so a per-QSO message always wins. Single choke
point covers both live preview and send.

frontend/src/components/SettingsModal.tsx

@@ -1373,8 +1373,8 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
   const [emailMsg, setEmailMsg] = useState('');
   const setEmailField = (patch: Partial<EmailCfg>) => setEmailCfg((s) => ({ ...s, ...patch }));
   // eQSL card e-mail (subject/body templates + auto-send on log).
-  type EQSLCfg = { subject: string; body: string; auto_send: boolean };
-  const [eqslCfg, setEqslCfg] = useState<EQSLCfg>({ subject: '', body: '', auto_send: false });
+  type EQSLCfg = { subject: string; body: string; auto_send: boolean; default_message: string };
+  const [eqslCfg, setEqslCfg] = useState<EQSLCfg>({ subject: '', body: '', auto_send: false, default_message: '' });
   const setEqslField = (patch: Partial<EQSLCfg>) => setEqslCfg((s) => ({ ...s, ...patch }));
   // ClubLog Country File (cty.xml) exception status.
   type ClubInfo = { enabled: boolean; loaded: boolean; date: string; count: number };
@@ -5836,6 +5836,12 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
             <div className="text-[11px] text-muted-foreground">
               {t('em.autoSendHint')}
             </div>
+            <div className="pt-2 space-y-1">
+              <Label className="text-sm">{t('em.qslDefaultMsg')}</Label>
+              <Input className="h-8" placeholder={t('em.qslDefaultMsgPh')} value={eqslCfg.default_message ?? ''}
+                onChange={(e) => setEqslField({ default_message: e.target.value })} />
+              <div className="text-[11px] text-muted-foreground">{t('em.qslDefaultMsgHint')}</div>
+            </div>
           </div>
         </div>
       </>