fix: fallback to timestamp in case if crypto context is not available

Previous tests have been done in either secure (HTTPS) or loopback
(localhost) environments, so I missed the case, that crypto methods
might not be available

Fixes #159

frontend/src/api/client/Client.ts

@@ -40,7 +40,7 @@ export class Client {
 
         const headers: Record<string, string> = {
             Accept: "application/json",
-            "X-Request-ID": crypto.randomUUID(),
+            "X-Request-ID": crypto.randomUUID?.() ?? Date.now().toString(),
         };
         if (json !== undefined) {
             headers["Content-Type"] = "application/json";