Refactor: Align system with gateway_users architecture

- Fixed database relationships: LlmRequest now properly uses gateway_user_id instead of user_id
- Updated Models: GatewayUser and LlmRequest relationships corrected
- Removed User->llmRequests relationship (admin users don't have LLM requests)
- Simplified Dashboard: Now shows Gateway User statistics instead of admin users
- Removed obsolete Budgets management pages (budgets handled directly in gateway_users)
- Removed User Budgets admin section (redundant with gateway_users management)
- Fixed view errors: Added null-checks for user_id in keys views
- Updated navigation: Removed Budget and User Budget links
- Updated routes: Cleaned up unused BudgetController and UserManagementController routes
- Simplified StatisticsService: Focus on gateway_users and basic metrics only

laravel-app/app/Services/StatisticsService.php

@@ -3,7 +3,7 @@
 namespace App\Services;
 
 use App\Models\LlmRequest;
-use App\Models\User;
+use App\Models\GatewayUser;
 use App\Models\UserProviderCredential;
 use Illuminate\Support\Facades\DB;
 
@@ -15,8 +15,9 @@ class StatisticsService
     public function getDashboardStats(): array
     {
         return [
-            'total_users' => User::count(),
-            'active_credentials' => UserProviderCredential::where('is_active', true)->count(),
+            'total_gateway_users' => GatewayUser::count(),
+            'active_gateway_users' => GatewayUser::where('blocked', false)->count(),
+            'blocked_gateway_users' => GatewayUser::where('blocked', true)->count(),
             'total_requests_today' => LlmRequest::whereDate('created_at', today())->count(),
             'total_spend_today' => LlmRequest::whereDate('created_at', today())->sum('total_cost') ?? 0,
             'total_tokens_today' => LlmRequest::whereDate('created_at', today())->sum('total_tokens') ?? 0,
@@ -73,11 +74,11 @@ class StatisticsService
     }
 
     /**
-     * Get top users by spend
+     * Get top gateway users by spend
      */
     public function getTopUsers(int $limit = 10)
     {
-        return User::select('users.*')
+        return GatewayUser::select('gateway_users.*')
             ->withCount('llmRequests')
             ->withSum('llmRequests as total_cost', 'total_cost')
             ->withSum('llmRequests as total_tokens', 'total_tokens')
@@ -91,18 +92,18 @@ class StatisticsService
      */
     public function getRecentActivity(int $limit = 20)
     {
-        return LlmRequest::with('user')
+        return LlmRequest::with('gatewayUser')
             ->orderByDesc('created_at')
             ->limit($limit)
             ->get();
     }
 
     /**
-     * Get user statistics
+     * Get gateway user statistics
      */
-    public function getUserStatistics(int $userId, int $days = 30)
+    public function getGatewayUserStatistics(string $gatewayUserId, int $days = 30)
     {
-        return LlmRequest::where('user_id', $userId)
+        return LlmRequest::where('gateway_user_id', $gatewayUserId)
             ->where('created_at', '>=', now()->subDays($days))
             ->where('status', 'success')
             ->selectRaw('