4/21/26 release branch (#3915)

* #3913 Update Events page

* #3912 Add 2 new CNAs  Update 1 CNA's info

* #3914 Add 1 VulnCon 2026 Thank You news page article

* #3912 Update 1 CNA's Root info

* npm update on 4/21/26

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Co-authored-by: Roy Lane <rlane@mitre.org>

Author: rroberge