Add Calyx Institute to signatories

Author: marcprux

public/img/logos/calyx.org.png

@@ -59,6 +59,12 @@
   social-bluesky: "https://bsky.app/profile/brave.com"
   social-x: "https://x.com/brave"
   social-linkedin: "https://linkedin.com/company/brave-software"
+- organization: "The Calyx Institute"
+  url: "calyx.org"
+  poc: "Sage Cheng <sage@calyx.org>"
+  region: "US"
+  social-mastodon: "https://mastodon.social/@calyxinstitute"
+  social-x: "https://x.com/calyxinstitute"
 - organization: "The Center for Digital Progress (D64)"
   url: "d-64.org"
   poc: "Esther Bauer - D64 – Zentrum für Digitalen Fortschritt <buero@d-64.org>"