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/smoke/test_smoke.py

@@ -102,19 +102,3 @@ async def test_webdav_basic_smoke(nc_mcp_client):
     data = json.loads(result.content[0].text)
     assert "files" in data
     assert isinstance(data["files"], list)
-
-
-@pytest.mark.oauth
-async def test_oauth_connectivity_smoke(nc_mcp_oauth_client):
-    """Smoke test: Verify OAuth authentication works."""
-    # List tools with OAuth
-    result = await nc_mcp_oauth_client.list_tools()
-    assert result is not None
-    assert len(result.tools) > 0
-
-    # Execute a simple tool
-    search_result = await nc_mcp_oauth_client.call_tool(
-        "nc_notes_search_notes",
-        arguments={"query": ""},
-    )
-    assert search_result.isError is False