Add one-sentence description for Euclid galaxy clusters tutorial

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

Author: jkrick

notebook_metadata.yml

@@ -22,6 +22,9 @@
 - title: Euclid Cloud Access
   file: tutorials/euclid/euclid-cloud-access.md
   description: Browse the on-cloud copy of Q1, then efficiently retrieve a MER mosaic cutout and a SIR spectrum.
+- title: Galaxy Clusters
+  file: tutorials/euclid/euclid_clusters_tutorial.md
+  description: Use Euclid Q1 data to detect and validate a galaxy cluster.
 - title: HATS with LSDB
   file: tutorials/techniques-and-tools/irsa-hats-with-lsdb.md
   description: Use LSDB for user-friendly cross matching and querying of HATS Collections.

tutorials/euclid/euclid.md

@@ -65,6 +65,12 @@ Magnitudes: Review the types of flux measurements available, load template-fit a
 Browse the on-cloud copy of Q1, then efficiently retrieve a MER mosaic cutout and a SIR spectrum.
 ```
 
+```{card}
+:link: euclid_clusters_tutorial.md
+:header: [Galaxy Clusters →](euclid_clusters_tutorial.md)
+Use Euclid Q1 data to detect and validate a galaxy cluster.
+```
+
 ```{card}
 :link: Euclid_ERO.md
 :header: [ERO Star Clusters →](Euclid_ERO.md)