Remove recent alumni entries pending further updates

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

Author: madan96

_data/alumni.yml

@@ -1,11 +1,3 @@
-- name: Krishna Palempalli
-  department: MEng, CS 2026
-  job: ""
-  website: https://krishnapranav21.wixsite.com/krishna-palempalli-s
-- name: Nayoung Sarah Ha
-  department: MEng, CS 2026
-  job: ""
-  website: https://nayoungsarahha.com
 - name: Tom Silver
   department: Postdoc, 2024-25
   job: Assistant Professor, Princeton