Fix API controllers to use correct database column names

- Fix model_pricing table references (model_id -> model, display_name -> model)
- Fix price columns (output_price_per_1k -> output_price_per_million)
- Add price conversion (per_million / 1000 = per_1k) in all API responses
- Add whereNotNull('model') filters to exclude invalid entries
- Add getModelDisplayName() helper method to all controllers
- Fix AccountController to use gateway_users budget fields directly
- Remove Budget model dependencies from AccountController
- Add custom Scramble server URL configuration for API docs
- Create ScrambleServiceProvider to set correct /api prefix
- Add migration to rename user_id to gateway_user_id in llm_requests
- Add custom ApiGuard for gateway_users authentication
- Update all API controllers: AccountController, ModelController, PricingController, ProviderController

All API endpoints now working correctly:
- GET /api/account
- GET /api/models
- GET /api/pricing
- GET /api/providers/{provider}

laravel-app/app/Http/Middleware/CheckBudget.php

@@ -4,28 +4,42 @@ namespace App\Http\Middleware;
 
 use Closure;
 use Illuminate\Http\Request;
-use App\Services\Budget\BudgetChecker;
 use Symfony\Component\HttpFoundation\Response;
 
 class CheckBudget
 {
-    public function __construct(
-        private BudgetChecker $budgetChecker
-    ) {}
-
     /**
      * Handle an incoming request.
+     * Check if gateway user has exceeded budget or is blocked.
      *
      * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
      */
     public function handle(Request $request, Closure $next): Response
     {
-        $user = $request->user();
+        $user = $request->user(); // GatewayUser from API Guard
 
-        if ($user) {
-            // Check budget before processing request
-            // Estimated cost is 0 for now, will be calculated after request
-            $this->budgetChecker->checkBudget($user, 0.0);
+        // Check if user is blocked
+        if ($user && $user->isBlocked()) {
+            return response()->json([
+                'error' => [
+                    'message' => 'User is blocked. Please contact your administrator.',
+                    'type' => 'user_blocked',
+                    'code' => 403,
+                ]
+            ], 403);
+        }
+
+        // Check if budget exceeded
+        if ($user && $user->hasExceededBudget()) {
+            return response()->json([
+                'error' => [
+                    'message' => 'Budget exceeded. Please contact your administrator.',
+                    'type' => 'budget_exceeded',
+                    'code' => 429,
+                    'budget_limit' => $user->monthly_budget_limit,
+                    'current_spending' => $user->current_month_spending,
+                ]
+            ], 429);
         }
 
         return $next($request);