The /oidc/[...] server catch-all was intercepting /oidc/login before
the Nuxt page router could render it. Moving the page outside /oidc/
avoids the conflict entirely.
Add oidc-provider with MongoDB adapter so ghostguild.org can act as
the identity provider for the self-hosted Outline wiki. Members
authenticate via the existing magic-link flow, with automatic SSO
when an active session exists. Includes interaction routes, well-known
discovery endpoint, and login page.
