fix: add X-Api-Key header to API feature tests and register auth routes

tests/Feature/Api/PredictionControllerTest.php

@@ -7,6 +7,10 @@ use Illuminate\Foundation\Testing\RefreshDatabase;
 
 uses(RefreshDatabase::class);
 
+beforeEach(function () {
+    $this->withHeaders(['X-Api-Key' => config('app.api_secret_key')]);
+});
+
 it('returns a prediction response for diesel', function () {
     $this->getJson('/api/prediction?fuel_type=diesel')
         ->assertOk()