Fix alumni website URL missing https prefix

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

Author: madan96

_data/alumni.yml

@@ -5,7 +5,7 @@
 - name: Nayoung Sarah Ha
   department: MEng, CS 2026
   job: ""
-  website: nayoungsarahha.com
+  website: https://nayoungsarahha.com
 - name: Tom Silver
   department: Postdoc, 2024-25
   job: Assistant Professor, Princeton