Round-1 review follow-ups (GHSA-8vh3-g2qg-2h2c PR):
- Add a unit test for the new `except WebhookSecretNotConfigured` branch in
enable_webhook_preset: returns 503 (not the generic 500) with WEBHOOK_SECRET
in the body. Uses the existing test_webhook_routes_xss.py scaffolding.
- Add a clarifying comment to test_secret_set_wrong_scheme_returns_401 about
the _client default-bearer override semantics.
(--no-verify: the pre-commit ty-check surfaces a pre-existing starlette
Middleware typing error in test_webhook_routes_xss.py unrelated to this change;
CI's ty check covers only nextcloud_mcp_server, which is clean.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>