fix(notifications): fall back when crypto.randomUUID is missing

If randomUUID is unavailable (older WebViews), generate a one-time ID
with Date.now + random segment, log a single DeviceId warning, and
persist it as before so registration still works.

src/services/notifications/deviceId.ts

@@ -3,7 +3,16 @@ import { Preferences } from "@capacitor/preferences";
 const DEVICE_ID_KEY = "stable_device_id";
 
 function generateDeviceId(): string {
-  return crypto.randomUUID();
+  if (typeof crypto !== "undefined" && crypto.randomUUID) {
+    return crypto.randomUUID();
+  }
+
+  // eslint-disable-next-line no-console
+  console.warn(
+    "[DeviceId] crypto.randomUUID unavailable, using fallback generator",
+  );
+
+  return `${Date.now()}-${Math.random().toString(36).slice(2)}`;
 }
 
 export async function getOrCreateDeviceId(): Promise<string> {