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/Http/Controllers/DashboardController.php

@@ -18,20 +18,12 @@ class DashboardController extends Controller
     {
         $stats = $this->statsService->getDashboardStats();
         $dailyUsage = $this->statsService->getDailyUsageChart(30);
-        $topUsers = $this->statsService->getTopUsers(5);
         $providerStats = $this->statsService->getUsageByProvider(30);
-        $modelStats = $this->statsService->getUsageByModel(30);
-        $costTrends = $this->statsService->getCostTrends(30);
-        $errorStats = $this->statsService->getErrorStats(30);
 
         return view('dashboard', compact(
             'stats',
             'dailyUsage',
-            'topUsers',
-            'providerStats',
-            'modelStats',
-            'costTrends',
-            'errorStats'
+            'providerStats'
         ));
     }