The auth routes no longer return 400 when the resolved request scheme
differs from MEALQUEST_PUBLIC_URL's. If Docker's published-port path
presents its bridge gateway instead of Traefik as the direct peer, the
forwarded headers are rightly ignored, but sign-in must still work: the
OIDC redirect URI and the Secure cookies are fixed by MEALQUEST_PUBLIC_URL,
not by the request. internal/auth is back to its state before the
trusted-proxy change; client IP and scheme resolution stays in the router.
Add TestLoginThroughRouter: it wires the real auth flow and session
manager through server.NewRouter, trusting Traefik only, and checks that
a login from Traefik and from an untrusted peer both redirect with the
redirect URI from MEALQUEST_PUBLIC_URL and set a Secure login cookie.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
