6307ce8bdc
Implement admin API endpoints for managing auth provider configuration: - GET /api/admin/auth-provider — get current config (secret redacted) - PUT /api/admin/auth-provider — create or update provider config - POST /api/admin/auth-provider/test — validate via OIDC discovery endpoint - DELETE /api/admin/auth-provider — remove DB config (falls back to env vars) All endpoints are gated by requireSuperUser(). The clientSecret is AES-256-GCM encrypted before DB write and always redacted on return. Test-connection fetches /.well-known/openid-configuration and returns metadata on success or error detail on failure. Includes 16 unit tests covering all endpoints and error paths. Co-Authored-By: Paperclip <noreply@paperclip.ing>