Add /events/collaborationfest/ redirect to latest CollaborationFest page

This makes open-bio.org/events/collaborationfest always point to the most
recent CollaborationFest page, matching the pattern used for /events/bosc/.

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

Author: nlharris

content/page/obf-bosc-collaborationfest-2026.md

@@ -7,6 +7,7 @@ url: /events/bosc-2026/collaborationfest
 aliases:
   - /events/bosc/collaborationfest2026/
   - /events/bosc/collaborationfest/
+  - /events/collaborationfest/
 bosc: yes
 ---