feat(auth): complete registration anti-spam and quota hardening

resources/views/auth/register.blade.php

@@ -17,8 +17,8 @@
                     <x-input-error :messages="$errors->get('email')" class="mt-2" />
                 </div>
 
-                @if(config('services.recaptcha.enabled'))
-                    <input type="hidden" name="g-recaptcha-response" value="{{ old('g-recaptcha-response') }}" />
+                @if(($requiresTurnstile ?? false) && ($turnstileSiteKey ?? '') !== '')
+                    <div class="cf-turnstile" data-sitekey="{{ $turnstileSiteKey }}"></div>
                     <x-input-error :messages="$errors->get('captcha')" class="mt-2" />
                 @endif
 
@@ -29,4 +29,7 @@
         </div>
     </div>
 </div>
+@if(($requiresTurnstile ?? false) && ($turnstileSiteKey ?? '') !== '')
+    <script src="https://challenges.cloudflare.com/turnstile/v0/api.js" async defer></script>
+@endif
 @endsection