test(auth): cover TOTP+key challenge branch; clarify mount comment

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Livewire/Auth/TwoFactorChallenge.php

@@ -24,8 +24,8 @@ class TwoFactorChallenge extends Component
             return $this->redirect(route('login'), navigate: true);
         }
 
-        // No TOTP and no usable security key (a key-only user over http + bare IP, where WebAuthn
+        // No TOTP and webauthnAvailable() is false (no registered key, or — for a key-only user —
-        // has no secure context) → the backup code is the only path: go straight to its own view.
+        // no secure context on http + bare IP) → the backup code is the only path: go to its view.
         if (! $this->pendingHasTotp && ! $this->webauthnAvailable()) {
             return $this->redirect(route('two-factor.challenge.backup'), navigate: true);
         }

tests/Feature/ChallengeFactorAdaptTest.php

@@ -67,4 +67,20 @@ class ChallengeFactorAdaptTest extends TestCase
             ->assertDontSee('000000')                              // no TOTP field
             ->assertDontSee(__('auth.challenge_backup_placeholder')); // no inline backup field
     }
+
+    public function test_totp_and_key_user_with_secure_context_sees_field_key_alt_and_backup(): void
+    {
+        $svc = $this->mock(WebauthnService::class);
+        $svc->shouldReceive('available')->andReturn(true);
+
+        $user = User::factory()->create(['two_factor_secret' => 'S', 'two_factor_confirmed_at' => now()]);
+        WebauthnCredential::create(['user_id' => $user->id, 'name' => 'k', 'credential_id' => 'cid', 'public_key' => '{}', 'sign_count' => 0]);
+        session(['2fa.user' => $user->id, '2fa.remember' => false]);
+
+        Livewire::test(TwoFactorChallenge::class)
+            ->assertNoRedirect()
+            ->assertSee('000000')                          // TOTP field
+            ->assertSee(__('auth.webauthn_login'))         // secondary security-key button (nested branch)
+            ->assertSee(__('auth.challenge_use_backup'));  // backup link
+    }
 }