Add single cake endpoint handler

internal/server/get.go

@@ -18,6 +18,25 @@ func (h *Server) cakes(r *http.Request) (any, int, error) {
 	return data, http.StatusOK, err
 }
 
+func (h *Server) cake(r *http.Request) (any, int, error) {
+	url := strings.Split(r.URL.String(), "/")
+	if len(url) < 3 || url[2] == "" {
+		return store.Cake{}, http.StatusOK, nil
+	}
+
+	id, err := strconv.Atoi(url[2])
+	if err != nil {
+		return nil, http.StatusBadRequest, err
+	}
+
+	data, err := h.s.GetCake(id)
+	if err != nil {
+		return nil, http.StatusNotFound, err
+	}
+
+	return data, http.StatusOK, nil
+}
+
 func (h *Server) order(r *http.Request) (any, int, error) {
 	type formData struct {
 		Order     store.Order