Mehrsprachigkeit der Oberfläche (Deutsch Standard, Englisch wählbar)

- Sprache je Benutzer (users.locale), Middleware SetLocale, Auswahl unter
  Einstellungen → Darstellung; angebotene Sprachen in config/app.php
- Übersetzungen über Laravel Lang (lang/de.json, lang/de/*.php), Seitentitel
  aus #[Title] werden übersetzt
- Eigene Texte und Korrekturen in lang/project/de.json, übernommen mit
  `artisan lang:apply-project` (überstehen `lang:update`)
- Tests: jede im Code verwendete Übersetzung ist vorhanden, eigene
  Übersetzungen sind übernommen, Sprachwahl und Standardsprache;
  SecurityTest prüft Texte sprachunabhängig über __()
- lang/ von Pint ausgenommen (erzeugte Dateien)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Feature/LocaleTest.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Livewire\Settings\Appearance;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+use Tests\TestCase;
+
+class LocaleTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_german_is_the_default_language(): void
+    {
+        $this->get(route('login'))
+            ->assertOk()
+            ->assertSee('<html lang="de"', false)
+            ->assertSee('Melden Sie sich bei Ihrem Konto an');
+    }
+
+    public function test_the_language_of_the_user_is_used(): void
+    {
+        $user = User::factory()->create(['locale' => 'en']);
+
+        $this->actingAs($user)
+            ->get(route('profile.edit'))
+            ->assertOk()
+            ->assertSee('<html lang="en"', false)
+            ->assertSee('Update your name and email address');
+    }
+
+    public function test_an_unknown_stored_language_falls_back_to_the_default(): void
+    {
+        $user = User::factory()->create(['locale' => 'xx']);
+
+        $this->actingAs($user)
+            ->get(route('profile.edit'))
+            ->assertOk()
+            ->assertSee('<html lang="de"', false);
+    }
+
+    public function test_appearance_page_offers_all_languages(): void
+    {
+        $response = $this->actingAs(User::factory()->create())
+            ->get(route('appearance.edit'))
+            ->assertOk()
+            ->assertSee('data-test="locale-select"', false)
+            ->assertSee('wire:model.live="locale"', false);
+
+        foreach (config('app.available_locales') as $code => $label) {
+            $response->assertSee('value="'.$code.'"', false)->assertSee($label);
+        }
+    }
+
+    public function test_users_can_change_their_language(): void
+    {
+        $user = User::factory()->create();
+
+        Livewire::actingAs($user)
+            ->test(Appearance::class)
+            ->assertSet('locale', 'de')
+            ->set('locale', 'en')
+            ->assertHasNoErrors()
+            ->assertRedirect(route('appearance.edit'));
+
+        $this->assertSame('en', $user->fresh()->locale);
+    }
+
+    public function test_only_offered_languages_can_be_chosen(): void
+    {
+        $user = User::factory()->create();
+
+        Livewire::actingAs($user)
+            ->test(Appearance::class)
+            ->set('locale', 'xx')
+            ->assertHasErrors('locale');
+
+        $this->assertNull($user->fresh()->locale);
+    }
+}

tests/Feature/Settings/SecurityTest.php

@@ -39,10 +39,10 @@ class SecurityTest extends TestCase
 
         $response->assertOk();
 
-        $response->assertSee('Passkeys');
-        $response->assertSee('No passkeys yet');
-        $response->assertSee('Two-factor authentication');
-        $response->assertSee('Enable 2FA');
+        $response->assertSee(__('Passkeys'));
+        $response->assertSee(__('No passkeys yet'));
+        $response->assertSee(__('Two-factor authentication'));
+        $response->assertSee(__('Enable 2FA'));
     }
 
     public function test_security_settings_page_requires_password_confirmation_when_enabled(): void
@@ -65,10 +65,10 @@ class SecurityTest extends TestCase
             ->withSession(['auth.password_confirmed_at' => time()])
             ->get(route('security.edit'))
             ->assertOk()
-            ->assertSee('Update password')
-            ->assertDontSee('Manage your passkeys for passwordless sign-in')
-            ->assertDontSee('Add a passkey to sign in without a password')
-            ->assertDontSee('Two-factor authentication');
+            ->assertSee(__('Update password'))
+            ->assertDontSee(__('Manage your passkeys for passwordless sign-in'))
+            ->assertDontSee(__('Add a passkey to sign in without a password'))
+            ->assertDontSee(__('Two-factor authentication'));
     }
 
     public function test_two_factor_authentication_disabled_when_confirmation_abandoned_between_requests(): void