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/GatewayUser.php

@@ -4,10 +4,12 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Contracts\Auth\Authenticatable;
+use Illuminate\Auth\Authenticatable as AuthenticatableTrait;
 
-class GatewayUser extends Model
+class GatewayUser extends Model implements Authenticatable
 {
-    use HasFactory;
+    use HasFactory, AuthenticatableTrait;
 
     protected $table = 'gateway_users';
     protected $primaryKey = 'user_id';
@@ -17,8 +19,10 @@ class GatewayUser extends Model
     protected $fillable = [
         'user_id',
         'alias',
-        'budget_id',
-        'spend',
+        'monthly_budget_limit',
+        'current_month_spending',
+        'budget_alert_threshold',
+        'rate_limit_per_hour',
         'blocked',
         'metadata',
     ];
@@ -26,48 +30,78 @@ class GatewayUser extends Model
     protected $casts = [
         'metadata' => 'array',
         'blocked' => 'boolean',
-        'spend' => 'decimal:2',
+        'monthly_budget_limit' => 'decimal:2',
+        'current_month_spending' => 'decimal:2',
         'created_at' => 'datetime',
         'updated_at' => 'datetime',
     ];
 
-    /**
-     * Get the budget associated with the user.
-     */
-    public function budget()
-    {
-        return $this->belongsTo(Budget::class, 'budget_id', 'budget_id');
-    }
-
-    /**
-     * Get the API keys for the user.
-     */
+    // Relationships
     public function apiKeys()
     {
-        return $this->hasMany(ApiKey::class, 'user_id', 'user_id');
+        return $this->hasMany(ApiKey::class, 'gateway_user_id', 'user_id');
+    }
+
+    public function credentials()
+    {
+        return $this->hasMany(GatewayUserCredential::class, 'user_id', 'user_id');
     }
 
-    /**
-     * Get the usage logs for the user.
-     */
     public function usageLogs()
     {
-        return $this->hasMany(UsageLog::class, 'user_id', 'user_id');
+        return $this->hasMany(UsageLog::class, 'gateway_user_id', 'user_id');
     }
 
-    /**
-     * Scope a query to only include active users.
-     */
+    // Scopes
     public function scopeActive($query)
     {
         return $query->where('blocked', false);
     }
 
-    /**
-     * Scope a query to only include blocked users.
-     */
     public function scopeBlocked($query)
     {
         return $query->where('blocked', true);
     }
+
+    // Helper methods for budget management
+    public function isBlocked(): bool
+    {
+        return $this->blocked;
+    }
+
+    public function hasExceededBudget(): bool
+    {
+        if (!$this->monthly_budget_limit) {
+            return false;
+        }
+        return $this->current_month_spending >= $this->monthly_budget_limit;
+    }
+
+    public function incrementSpending(float $amount): void
+    {
+        $this->increment('current_month_spending', $amount);
+    }
+
+    public function resetMonthlySpending(): void
+    {
+        $this->update(['current_month_spending' => 0]);
+    }
+
+    public function getBudgetUsagePercentage(): ?float
+    {
+        if (!$this->monthly_budget_limit || $this->monthly_budget_limit == 0) {
+            return null;
+        }
+        return ($this->current_month_spending / $this->monthly_budget_limit) * 100;
+    }
+
+    public function shouldSendBudgetAlert(): bool
+    {
+        if (!$this->budget_alert_threshold || !$this->monthly_budget_limit) {
+            return false;
+        }
+        
+        $percentage = $this->getBudgetUsagePercentage();
+        return $percentage !== null && $percentage >= $this->budget_alert_threshold;
+    }
 }