feat(hamlog): confirmation defaults and grid columns; drop a settings paragraph

Preferences → Confirmations gains a HAMLOG.online row, sent and received, with
the same defaults every other service has: a new QSO can start at N so the
backlog is meaningful from the first contact. The defaults reach it through a
new setExtraDefault — fill() writes through a pointer to a string field and
these two live in the extras map, which no pointer reaches.

The QSO grid gains four HAMLOG columns (status and date, both directions),
hidden by default: a column per service shown to everyone is how a grid becomes
unreadable.

And the paragraph explaining what "Sent" means is gone from that page.

frontend/wailsjs/go/models.ts

@@ -3032,6 +3032,8 @@ export namespace main {
 	    hrdlog_status: string;
 	    qrzcom_status: string;
 	    qrzcom_confirmed: string;
+	    hamlog_status: string;
+	    hamlog_confirmed: string;
 	
 	    static createFrom(source: any = {}) {
 	        return new QSLDefaults(source);
@@ -3049,6 +3051,8 @@ export namespace main {
 	        this.hrdlog_status = source["hrdlog_status"];
 	        this.qrzcom_status = source["qrzcom_status"];
 	        this.qrzcom_confirmed = source["qrzcom_confirmed"];
+	        this.hamlog_status = source["hamlog_status"];
+	        this.hamlog_confirmed = source["hamlog_confirmed"];
 	    }
 	}
 	export class QSLEmailTemplates {