internal/rosa: panic error for invalid handle

This enables recovery and better error handling for errors originating from external azalea files.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -58,6 +58,19 @@ func main() {
 		log.Fatal("this program must not run as root")
 	}
 
+	defer func() {
+		r := recover()
+		if r == nil {
+			return
+		}
+
+		h, ok := r.(rosa.HandleError)
+		if !ok {
+			panic(r)
+		}
+		log.Fatal(h)
+	}()
+
 	ctx, stop := signal.NotifyContext(context.Background(),
 		syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
 	defer stop()