feat(api): add card-to-iban HTTP endpoint

backend/internal/httpapi/cors.go

@@ -0,0 +1,25 @@
+package httpapi
+
+import "net/http"
+
+func AllowOrigin(
+	origin string,
+	next http.Handler,
+) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Vary", "Origin")
+
+		if r.Header.Get("Origin") == origin {
+			w.Header().Set("Access-Control-Allow-Origin", origin)
+			w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+			w.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS")
+
+			if r.Method == http.MethodOptions {
+				w.WriteHeader(http.StatusNoContent)
+				return
+			}
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}