fix(client): avoid crypto.randomUUID() TypeError by adding uuid helper

Add a small, robust UUID helper and replace direct uses of crypto.randomUUID()
in the client to avoid a runtime TypeError in browsers/environments that do not
implement crypto.randomUUID which caused the frontend to crash and show the
"Browser not supported / JavaScript changes.

Author: Matthias Kastner

client/src/lib/components/Toggle.svelte

@@ -3,10 +3,11 @@
     label: string;
     checked?: boolean;
   }
+  import { uuid } from '$lib/uuid';
 
   let { label, checked = $bindable(), class: extraClass = '', ...rest }: Props = $props();
 
-  const id = `toggle-${crypto.randomUUID()}`;
+  const id = `toggle-${uuid()}`;
 </script>
 
 <div class="flex items-center gap-2 {extraClass}">

client/src/lib/utils.ts

@@ -1,3 +1,5 @@
+import { uuid } from './uuid';
+
 declare const umami: {
   track: (event_name: string, data?: Record<string, any>) => void;
   identify: (unique_id: string) => void;
@@ -11,7 +13,7 @@ export function initializeAnalytics(): void {
     const umamiIdKey = 'mvw_uuid';
     let uniqueId = localStorage.getItem(umamiIdKey);
     if (!uniqueId) {
-      uniqueId = crypto.randomUUID();
+      uniqueId = uuid();
       localStorage.setItem(umamiIdKey, uniqueId);
     }
     umami.identify(uniqueId);

client/src/lib/uuid.ts

@@ -0,0 +1,23 @@
+export function uuid(): string {
+  if (typeof globalThis !== 'undefined' && globalThis.crypto && typeof globalThis.crypto.randomUUID === 'function') {
+    return globalThis.crypto.randomUUID();
+  }
+
+  if (typeof globalThis !== 'undefined' && globalThis.crypto && typeof globalThis.crypto.getRandomValues === 'function') {
+    const bytes = globalThis.crypto.getRandomValues(new Uint8Array(16));
+    // RFC4122 v4
+    bytes[6] = (bytes[6] & 0x0f) | 0x40;
+    bytes[8] = (bytes[8] & 0x3f) | 0x80;
+    const hex = Array.from(bytes, (b) => b.toString(16).padStart(2, '0')).join('');
+    return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20, 32)}`;
+  }
+
+  // Last-resort fallback (not cryptographically secure)
+  const hexChars = '0123456789abcdef';
+  const s: string[] = new Array(36);
+  for (let i = 0; i < 36; i++) s[i] = hexChars[(Math.random() * 16) | 0];
+  s[14] = '4';
+  s[19] = hexChars[(parseInt(s[19], 16) & 0x3) | 0x8];
+  s[8] = s[13] = s[18] = s[23] = '-';
+  return s.join('');
+}