Add production observability: Sentry, pino, and sharp badge encoding.

Sentry is opt-in via DSN env vars; logger uses structured pino JSON in prod; badge uploads are normalized to GIF with sharp.

Co-authored-by: Cursor <[email protected]>

src/app/global-error.tsx

@@ -1,5 +1,6 @@
 "use client";
 
+import * as Sentry from "@sentry/nextjs";
 import { useEffect } from "react";
 
 /**
@@ -15,7 +16,7 @@ export default function GlobalError({
 	reset: () => void;
 }) {
 	useEffect(() => {
-		console.error(error);
+		Sentry.captureException(error);
 	}, [error]);
 
 	return (