Default Grafana auto-assign role to Editor

Users land via GitHub OAuth gated by the trails-cool org allowlist, so
Viewer-only is more restrictive than we actually want — no Explore
access, no ad-hoc Loki/Prometheus queries. Promote the default role to
Editor so new sign-ins get it automatically.

Note: GF_USERS_AUTO_ASSIGN_ORG_ROLE only applies to new users on first
sign-in. Existing Viewers (including the single current user) need a
one-off promotion via the Grafana admin UI.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

infrastructure/docker-compose.yml

@@ -201,6 +201,11 @@ services:
       GF_AUTH_GITHUB_SCOPES: user:email,read:org
       GF_AUTH_OAUTH_ALLOW_INSECURE_EMAIL_LOOKUP: "true"
       GF_AUTH_DISABLE_LOGIN_FORM: "true"
+      # New GitHub-authenticated users land as Editor, not the default
+      # Viewer, so they can use Explore (ad-hoc Loki/Prometheus queries)
+      # without an admin promotion step. Access is already gated by the
+      # GF_AUTH_GITHUB_ALLOWED_ORGANIZATIONS allowlist above.
+      GF_USERS_AUTO_ASSIGN_ORG_ROLE: Editor
       GF_SMTP_ENABLED: "true"
       GF_SMTP_HOST: ${GF_SMTP_HOST:-}
       GF_SMTP_USER: ${GF_SMTP_USER:-}