Add Rybbit analytics alongside Umami

- Load Rybbit script via app.html (recommended SvelteKit approach)
- Mirror all Umami custom events (First guess, Guessed correctly, Share, Copy to Clipboard, social link clicks) with rybbit.event()
- Identify logged-in users with name/email traits; anonymous users by stable UUID

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

src/lib/components/Credits.svelte

@@ -34,6 +34,7 @@
 			class="inline-flex hover:opacity-80 transition-opacity"
 			aria-label="Follow on Bluesky"
 			data-umami-event="Bluesky clicked"
+			onclick={() => (window as any).rybbit?.event("Bluesky clicked")}
 		>
 			<img src={BlueskyLogo} alt="Bluesky" class="w-8 h-8" />
 		</a>
@@ -47,6 +48,7 @@
 			class="inline-flex hover:opacity-80 transition-opacity"
 			aria-label="Follow on Twitter"
 			data-umami-event="Twitter clicked"
+			onclick={() => (window as any).rybbit?.event("Twitter clicked")}
 		>
 			<img src={TwitterLogo} alt="Twitter" class="w-8 h-8" />
 		</a>
@@ -58,6 +60,7 @@
 			class="inline-flex hover:opacity-80 transition-opacity"
 			aria-label="Send email"
 			data-umami-event="Email clicked"
+			onclick={() => (window as any).rybbit?.event("Email clicked")}
 		>
 			<svg
 				class="w-8 h-8 text-gray-700"