Make the magic-link resend cooldown configurable

EmailVerifier::RESEND_INTERVAL_SECONDS was a hardcoded class constant
shared (via a copy-of-a-constant) by AuthController and
EmailVerificationController. It's now a constructor param
(resendIntervalSeconds, default 60, same as before) sourced from
Config -- new MAGIC_LINK_RESEND_SECONDS env var, default unchanged.

Docker Compose sets it to 0, so magic links resend immediately during
local development instead of waiting out the throttle.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/Http/Controllers/AuthController.php

@@ -83,6 +83,6 @@ final class AuthController extends Controller
         $lastSent = $user['verification_email_sent_at'] ?? null;
 
         return $lastSent !== null
-            && (time() - (int) strtotime($lastSent)) < EmailVerifier::RESEND_INTERVAL_SECONDS;
+            && (time() - (int) strtotime($lastSent)) < $this->verifier->resendIntervalSeconds;
     }
 }

src/Http/Controllers/EmailVerificationController.php

@@ -16,7 +16,6 @@ use Psr\Http\Message\ServerRequestInterface as Request;
 
 final class EmailVerificationController extends Controller
 {
-    private const RESEND_INTERVAL_SECONDS = EmailVerifier::RESEND_INTERVAL_SECONDS;
     private const EMAIL_MAX = 255;
 
     public function __construct(
@@ -115,7 +114,7 @@ final class EmailVerificationController extends Controller
         return $this->json($response, [
             'message' => 'Confirmation email sent to the new address.',
             'pending_email' => $newEmail,
-            'retry_after' => self::RESEND_INTERVAL_SECONDS,
+            'retry_after' => $this->verifier->resendIntervalSeconds,
         ], 202);
     }
 
@@ -130,11 +129,11 @@ final class EmailVerificationController extends Controller
         }
 
         $elapsed = time() - (int) strtotime($lastSent);
-        if ($elapsed < self::RESEND_INTERVAL_SECONDS) {
+        if ($elapsed < $this->verifier->resendIntervalSeconds) {
             throw new ApiException(
                 'Please wait a moment before requesting another email.',
                 429,
-                ['retry_after' => self::RESEND_INTERVAL_SECONDS - $elapsed],
+                ['retry_after' => $this->verifier->resendIntervalSeconds - $elapsed],
             );
         }
     }