The scope-middleware injection on the public driver registration
endpoints (POST /subusers and POST /subusers/me) breaks the public
registration contract — new drivers cannot hold a scope before they
exist, so requiring one would make self-registration impossible.
PublicSubuserRegistrationContractTest enforces the literal
'POST /subusers → registerPublicSubuser' / 'POST /subusers/me →
registerPublicSubuser' signature. Adding the ScopeMiddleware call
violates that contract and fails the test.
Drop the ScopeMiddleware::requireScope() call from both public
registration handlers; the in-method abuse controls (recaptcha,
rate limits, MySQL GET_LOCK) remain the only gate, as before.
Fixes CI on PR #397 (Required CI, PHP unit, PHP api, PHP integration).
