Cursor's Admin API authenticates with the admin key as the HTTP
Basic auth username (empty password) and rejects Bearer tokens.
The API-key connection previously supported only Bearer and a
custom header (Anthropic's x-api-key); add a Basic-auth mode
selected by Registration.APIKeyBasicAuth, and reject providers
that set both it and APIKeyHeader.
Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>
0149ca4f55