fix: run Gitea admin user creation command as 'git' user in Unraid

phase1_gitea_unraid.sh

@@ -145,7 +145,7 @@ else
   # Create admin via CLI inside the container (not the API) because no API
   # token exists yet at this point. || true prevents set -e from exiting if
   # the user was partially created in a previous interrupted run.
-  ssh_exec UNRAID "docker exec gitea gitea admin user create \
+  ssh_exec UNRAID "docker exec -u git gitea gitea admin user create \
     --username '${GITEA_ADMIN_USER}' \
     --password '${GITEA_ADMIN_PASSWORD}' \
     --email '${GITEA_ADMIN_EMAIL}' \