keep the Sepolia node snapshot link

Restore both snapshot URLs, annotating the Sepolia one with the
shutdown date rather than dropping it.

Author: roylou

src/content/docs/en/developers/index.mdx

@@ -75,7 +75,9 @@ Use our [Dune dashboard](https://docs.scroll.io/en/developers/developer-ecosyste
 
 **Where can i download Scroll node's snapshot?**
 
-https://snapshot.scroll.io/mpt/latest.tar
+Mainnet : https://snapshot.scroll.io/mpt/latest.tar
+
+Sepolia : https://snapshot.scroll.io/sepolia/mpt/latest.tar (Scroll Sepolia was shut down after July 30th, 2026 — kept for historical reference)
 
 **Scroll snapshot size is too large, do you have pruned snapshot?**