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/Models/UsageLog.php

@@ -17,7 +17,7 @@ class UsageLog extends Model
 
     protected $fillable = [
         'request_id',
-        'user_id',
+        'gateway_user_id',  // Changed from user_id
         'api_key',
         'model',
         'provider',
@@ -30,6 +30,11 @@ class UsageLog extends Model
         'error_message',
         'timestamp',
         'metadata',
+        'request_payload',
+        'response_payload',
+        'response_time_ms',
+        'ip_address',
+        'user_agent',
     ];
 
     protected $casts = [
@@ -39,16 +44,15 @@ class UsageLog extends Model
         'cost' => 'decimal:6',
         'timestamp' => 'datetime',
         'metadata' => 'array',
+        'request_payload' => 'array',
+        'response_payload' => 'array',
+        'response_time_ms' => 'integer',
     ];
 
-    public function user()
-    {
-        return $this->belongsTo(GatewayUser::class, 'user_id', 'user_id');
-    }
-
+    // Relationships
     public function gatewayUser()
     {
-        return $this->belongsTo(GatewayUser::class, 'user_id', 'user_id');
+        return $this->belongsTo(GatewayUser::class, 'gateway_user_id', 'user_id');
     }
 
     public function apiKey()
@@ -66,4 +70,19 @@ class UsageLog extends Model
     {
         return $query->where('status', 'failed');
     }
+
+    public function scopeRecent($query, $days = 7)
+    {
+        return $query->where('timestamp', '>=', now()->subDays($days));
+    }
+
+    public function scopeByProvider($query, string $provider)
+    {
+        return $query->where('provider', $provider);
+    }
+
+    public function scopeByModel($query, string $model)
+    {
+        return $query->where('model', $model);
+    }
 }