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/routes/+page.svelte

@@ -47,7 +47,7 @@
 		() => dailyVerse.date,
 		() => dailyVerse.reference,
 		() => correctBookId,
-		() => user?.id,
+		() => user,
 	);
 
 	let guessedIds = $derived(
@@ -86,6 +86,7 @@
 				(window as any).umami
 			) {
 				(window as any).umami.track("First guess");
+				(window as any).rybbit?.event("First guess");
 				localStorage.setItem(key, "true");
 			}
 		}
@@ -209,6 +210,9 @@
 			(window as any).umami.track("Guessed correctly", {
 				totalGuesses: persistence.guesses.length,
 			});
+			(window as any).rybbit?.event("Guessed correctly", {
+				totalGuesses: persistence.guesses.length,
+			});
 		}
 	});