refactor: remove oauth profile, migrate MCP/OAuth tests to login-flow

Remove the oauth Docker Compose profile (mcp-oauth service, port 8001)
which used OAuth bearer tokens for direct NC API access, requiring
upstream OIDC patches. All NC access should use app passwords via
Login Flow v2 or BasicAuth.

Changes:
- Remove mcp-oauth service from docker-compose.yml
- Remove oauth mode from CI test matrix
- Delete oauth pass-through tests (core, permissions, token exchange)
- Delete oauth-specific tests (elicitation, NC PHP app, astrolabe)
- Migrate MCP/OAuth integration tests to login-flow profile:
  - DCR lifecycle, deletion, token type tests
  - Scope authorization (tool filtering) tests
  - Token introspection tests
- Fix flaky consent screen automation: replace JS btn.click() with
  Playwright native click + retry (handles Vue.js event binding race)
- Add scope-filtered OAuth client fixtures to login-flow conftest
- Keep keycloak profile for external IdP testing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/server/auth/test_userinfo_routes.py

@@ -1,11 +1,6 @@
 """Unit tests for user info routes.
 
-Note: Most unit tests were removed as they relied on the old _get_user_info API.
-The new browser OAuth session-based implementation is covered by integration tests
-in tests/server/oauth/test_userinfo_integration.py which test the full OAuth flow
-with real browser sessions, token storage, and IdP interactions.
-
-These unit tests cover only the simple _query_idp_userinfo helper function.
+These unit tests cover the simple _query_idp_userinfo helper function.
 """
 
 from unittest.mock import AsyncMock, Mock