implement auth controller and routes

Wires AuthController (signup, confirmEmail, login, me, logout)
to the existing auth use cases. Routes mounted under /api with
AuthMiddleware on logout/me. RepositoryServiceProvider gains
EmailConfirmationToken and Post bindings; AppServiceProvider
binds the Emailer/EmailFactory and constructs SignupUser with
the configured from-address.

backend/app/Providers/AppServiceProvider.php

@@ -8,6 +8,14 @@ use App\Auth\PasswordHasher;
 use App\Auth\RandomTokenGenerator;
 use App\Auth\SystemClock;
 use App\Auth\TokenGenerator;
+use App\Email\EmailConfirmationToken\EmailConfirmationTokenRepository;
+use App\Email\Emailer;
+use App\Email\EmailFactory;
+use App\Email\LaravelEmailFactory;
+use App\Email\LaravelMailer;
+use App\User\UseCases\SignupUser\SignupUser;
+use App\User\UserRepository;
+use Illuminate\Contracts\Foundation\Application;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -17,6 +25,31 @@ class AppServiceProvider extends ServiceProvider
         $this->app->bind(Clock::class, SystemClock::class);
         $this->app->bind(TokenGenerator::class, RandomTokenGenerator::class);
         $this->app->bind(PasswordHasher::class, BcryptPasswordHasher::class);
+        $this->app->bind(Emailer::class, LaravelMailer::class);
+        $this->app->bind(
+            EmailFactory::class,
+            function () {
+                return new LaravelEmailFactory(
+                    confirmationUrlPrefix: config('app.frontend_url')
+                        .'/confirm-email?token=',
+                );
+            },
+        );
+        $this->app->bind(
+            SignupUser::class,
+            function (Application $app) {
+                return new SignupUser(
+                    userRepo: $app->make(UserRepository::class),
+                    tokenRepo: $app->make(
+                        EmailConfirmationTokenRepository::class,
+                    ),
+                    emailer: $app->make(Emailer::class),
+                    emailFactory: $app->make(EmailFactory::class),
+                    clock: $app->make(Clock::class),
+                    fromAddress: config('mail.from.address'),
+                );
+            },
+        );
     }
 
     public function boot(): void

backend/app/Providers/RepositoryServiceProvider.php

@@ -4,6 +4,10 @@ namespace App\Providers;
 
 use App\Auth\EloquentSessionRepository;
 use App\Auth\SessionRepository;
+use App\Email\EmailConfirmationToken\EloquentEmailConfirmationTokenRepository;
+use App\Email\EmailConfirmationToken\EmailConfirmationTokenRepository;
+use App\Post\EloquentPostRepository;
+use App\Post\PostRepository;
 use App\User\EloquentUserRepository;
 use App\User\UserRepository;
 use Illuminate\Support\ServiceProvider;
@@ -20,5 +24,13 @@ class RepositoryServiceProvider extends ServiceProvider
             SessionRepository::class,
             EloquentSessionRepository::class,
         );
+        $this->app->bind(
+            EmailConfirmationTokenRepository::class,
+            EloquentEmailConfirmationTokenRepository::class,
+        );
+        $this->app->bind(
+            PostRepository::class,
+            EloquentPostRepository::class,
+        );
     }
 }