feat: add Random Generator tool

Cryptographically secure generator for 5 types:
- Password: configurable charset + entropy strength meter
- UUID: crypto.randomUUID()
- API Key: hex/base62/base64url with optional prefix
- Hash: SHA-1/256/512 of custom input or random data
- Token: variable byte-length in hex or base64url

All using Web Crypto API — nothing leaves the browser.
Registered in lib/tools.tsx with RandomIcon (dice).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/(app)/random/page.tsx

@@ -0,0 +1,16 @@
+import type { Metadata } from 'next';
+import { RandomGenerator } from '@/components/random/RandomGenerator';
+import { AppPage } from '@/components/layout/AppPage';
+import { getToolByHref } from '@/lib/tools';
+
+const tool = getToolByHref('/random')!;
+
+export const metadata: Metadata = { title: tool.title, description: tool.summary };
+
+export default function RandomPage() {
+  return (
+    <AppPage>
+      <RandomGenerator />
+    </AppPage>
+  );
+}