Disable Slack in Garand-Desktop system modules

hosts/Garand-Desktop/system-modules.nix

@@ -77,7 +77,7 @@ _: {
     Communication & Collaboration
     */
     mattermost.enable = true; # Mattermost: open‑source Slack alternative
-    slack.enable = true; # Slack: team communication and collaboration tool
+    slack.enable = false; # Slack: team communication and collaboration tool
     tutanota.enable = true; # Tutanota: secure email client
     signal.enable = true; # Signal: secure messaging app
     teams.enable = true; # Teams-for-linux: Unofficial Microsoft Teams client for Linux