- webhook_receiver: always run hmac.compare_digest (drop the
`not provided or` short-circuit) so the constant-time path is
taken regardless of whether the Authorization header is present.
- client/webhooks: modernise the new `auth_data` type hint to
`dict[str, str] | None` per CLAUDE.md.
- tests/client: rename `test_create_webhook_with_auth_headers` →
`test_create_webhook_with_static_headers` and use
`auth_method="header"` (NC's webhook_listeners only supports
"none" and "header"; the previous "bearer" value was invalid).
- auth/webhook_routes: extract `_register_preset_webhooks` from
`enable_webhook_preset` so the auth-threading behaviour is
testable without standing up a Starlette app + auth middleware.
- tests/unit: new test_webhook_routes_register covering the helper
with secret set / unset, and verifying ids round-trip in order.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
