fix(ci): revert accidental third_party mount, use compose override for OIDC

The third_party:/opt/apps volume was accidentally uncommented in
docker-compose.yml. Without submodules checked out, this empty mount
breaks the Notes app installation hook in CI.

Fix: keep the mount commented in docker-compose.yml and add a separate
docker-compose.oidc.yml override that's only used for OIDC-requiring
profiles (oauth, login-flow) in CI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -35,7 +35,7 @@ services:
       - ./app-hooks:/docker-entrypoint-hooks.d:ro
       # Mount OIDC development directory outside /var/www/html to avoid rsync conflicts
       # The post-installation hook will register /opt/apps as an additional app directory
-      - ./third_party:/opt/apps:ro
+      #- ./third_party:/opt/apps:ro
     environment:
       - NEXTCLOUD_TRUSTED_DOMAINS=app
       - NEXTCLOUD_ADMIN_USER=admin