The OAuth flow uses grant_type=mobile with a server-issued grant
(app/api/auth/token/route.js); no client_id/client_secret is sent at
runtime. These vars were dead — removed from Dockerfile args/env,
docker-compose, nixpacks, and docs. Also silences the Coolify
'variable not set' build warnings.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>