feat: mattermost zitadel oidc sso (#1796)

Author: zackpollard

tf/deployment/modules/shared/zitadel/cloud/project.tf

@@ -73,6 +73,12 @@ locals {
       redirectUris           = ["https://login.netbird.io/login/callback"]
       postLogoutRedirectUris = ["https://app.netbird.io"]
     },
+    {
+      name         = "Mattermost"
+      roles        = [{ key = "Granted", grants_to = ["immich_admin", "team", "futo"] }]
+      authMethod   = "BASIC"
+      redirectUris = ["https://mattermost.futo.tech/signup/openid/complete"]
+    },
     {
       name = "Yucca Internal Tooling"
       # redirectUris intentionally empty for now — public/PKCE client