feat(matrix): mark the slots already worked with the callsign in hand

The worked-before cell answered one question with two facts fused into it.
bandStatusCode takes the highest of them, so a confirmed entity outranks a
worked callsign — right for awards, wrong while chasing: a slot worked with the
DXpedition this morning reads "entity confirmed" and says nothing about it.

BandStatus now carries the callsign's own answer alongside the entity's, and the
cell draws a dot for it. The dot is deliberately identical everywhere — same
shape, same colour, over all five backgrounds — so it is read as one thing
rather than as five variants of the colour underneath it.

frontend/wailsjs/go/models.ts

@@ -5027,6 +5027,7 @@ export namespace qso {
 	    band: string;
 	    class: string;
 	    status: string;
+	    call?: string;
 	
 	    static createFrom(source: any = {}) {
 	        return new BandStatus(source);
@@ -5037,6 +5038,7 @@ export namespace qso {
 	        this.band = source["band"];
 	        this.class = source["class"];
 	        this.status = source["status"];
+	        this.call = source["call"];
 	    }
 	}
 	export class Bucket {