OIDC configuration now comes from environment variables instead of
the database settings table. This is more natural for Docker/compose
deployments where secrets live in .env files.
Env vars: OIDC_ENABLED, OIDC_DISCOVERY_URL, OIDC_CLIENT_ID,
OIDC_CLIENT_SECRET, OIDC_REDIRECT_URI, OIDC_BUTTON_LABEL.
Also adds detailed [oidc] console logging throughout the authorize,
callback, and link flows to aid debugging connection issues.
Removes the OIDC settings UI section from the admin modal and the
GET/PUT /api/settings/oidc endpoints.
steve
da5d436432