fix(ui): the opening badge must say what is open, not that something is

It read "6M OPEN" and kept the rest in a tooltip nobody hovers — an alarm with
no content, announcing that something was happening and refusing to say what.
Band, direction and typical distance are on the badge now: the three facts that
decide whether to point an antenna, all readable without touching anything. Out
of season gets a mark there too, since that is the one an operator must not
learn last.

The compass point is computed in Go and carried on the Opening rather than
derived in the UI. Sector() already gets the wrap round north right, and it got
it wrong once — a second copy of that arithmetic is how a badge ends up naming
the opposite direction to the log line beside it.

frontend/wailsjs/go/models.ts

@@ -685,6 +685,7 @@ export namespace bandopen {
 	    median_km: number;
 	    bearing_min: number;
 	    bearing_max: number;
+	    compass: string;
 	    in_season: boolean;
 	    // Go type: time
 	    at: any;
@@ -701,6 +702,7 @@ export namespace bandopen {
 	        this.median_km = source["median_km"];
 	        this.bearing_min = source["bearing_min"];
 	        this.bearing_max = source["bearing_max"];
+	        this.compass = source["compass"];
 	        this.in_season = source["in_season"];
 	        this.at = this.convertValues(source["at"], null);
 	        this.examples = source["examples"];