Self-hosting login_flow against Nextcloud's built-in `oidc` app breaks after
~1h when relying on the DCR fallback: the `oidc` app deletes
dynamically-registered clients after `client_expire_time` (default 3600s),
pruning on every /authorize. The MCP server caches the now-deleted client, so
authorize/refresh fail with an "Access forbidden" page permanently — surviving
server restart and connector recreation (issue #907).
- docs/login-flow-v2.md: add "Default IdP setup (Nextcloud oidc app)" with
static-client steps, and a Troubleshooting entry for the #907 symptom/fix;
reframe the OIDC-client env vars as strongly recommended.
- docs/configuration.md: promote NEXTCLOUD_OIDC_CLIENT_ID/_SECRET to strongly
recommended with a DCR-expiry warning; add them to the login_flow example.
- docker-compose.yml: clarify the DCR caveat and point self-hosters to a static
client for login_flow / background sync.
- env.sample.oauth-multi-user: fix the removed `oauth_single_audience` value
(now login_flow) and require a static OIDC client.
- env.sample.oauth-advanced: remove — it configured the removed OAuth
token-exchange mode (no implementation remains; the mode value now errors at
startup). Drop its references in configuration.md / configuration-migration-v2.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
