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/Services/LLM/RequestLogger.php

@@ -9,9 +9,20 @@ class RequestLogger
 {
     /**
      * Log a successful LLM request
+     *
+     * @param string $gatewayUserId Gateway user ID (user_id from gateway_users)
+     * @param string $provider Provider name
+     * @param string $model Model name
+     * @param array $requestPayload Request payload
+     * @param array $responsePayload Response payload
+     * @param array $costs Cost breakdown
+     * @param int $responseTimeMs Response time in milliseconds
+     * @param string|null $ipAddress Client IP address
+     * @param string|null $userAgent Client user agent
+     * @return string Request ID
      */
     public function logSuccess(
-        int $userId,
+        string $gatewayUserId,
         string $provider,
         string $model,
         array $requestPayload,
@@ -24,7 +35,7 @@ class RequestLogger
         $requestId = $this->generateRequestId();
 
         LogLlmRequest::dispatch(
-            userId: $userId,
+            userId: $gatewayUserId,
             provider: $provider,
             model: $model,
             requestPayload: $requestPayload,
@@ -49,9 +60,19 @@ class RequestLogger
 
     /**
      * Log a failed LLM request
+     *
+     * @param string $gatewayUserId Gateway user ID (user_id from gateway_users)
+     * @param string $provider Provider name
+     * @param string $model Model name
+     * @param array $requestPayload Request payload
+     * @param string $errorMessage Error message
+     * @param int $httpStatus HTTP status code
+     * @param string|null $ipAddress Client IP address
+     * @param string|null $userAgent Client user agent
+     * @return string Request ID
      */
     public function logFailure(
-        int $userId,
+        string $gatewayUserId,
         string $provider,
         string $model,
         array $requestPayload,
@@ -63,7 +84,7 @@ class RequestLogger
         $requestId = $this->generateRequestId();
 
         LogLlmRequest::dispatch(
-            userId: $userId,
+            userId: $gatewayUserId,
             provider: $provider,
             model: $model,
             requestPayload: $requestPayload,