Add complete Laravel LLM Gateway implementation

Core Features:
- Multi-provider support (OpenAI, Anthropic, DeepSeek, Gemini, Mistral)
- Provider service architecture with abstract base class
- Dynamic model discovery from provider APIs
- Encrypted per-user provider credentials storage

Admin Interface:
- Complete admin panel with Livewire components
- User management with CRUD operations
- API key management with testing capabilities
- Budget system with limits and reset schedules
- Usage logs with filtering and CSV export
- Model pricing management with cost calculator
- Dashboard with Chart.js visualizations

Database Schema:
- MariaDB migrations for all tables
- User provider credentials (encrypted)
- LLM request logging
- Budget tracking and rate limiting
- Model pricing configuration

API Implementation:
- OpenAI-compatible endpoints
- Budget checking middleware
- Rate limit enforcement
- Request logging jobs
- Cost calculation service

Testing:
- Unit tests for all provider services
- Provider factory tests
- Cost calculator tests

Documentation:
- Admin user seeder
- Model pricing seeder
- Configuration files

laravel-app/app/Http/Controllers/Admin/UserManagementController.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Http\Controllers\Admin;
+
+use App\Http\Controllers\Controller;
+use App\Models\User;
+use Illuminate\Http\Request;
+
+class UserManagementController extends Controller
+{
+    /**
+     * Display a listing of users with budget info
+     */
+    public function index(Request $request)
+    {
+        $query = User::with(['budget', 'rateLimit', 'llmRequests'])
+            ->withCount('llmRequests');
+
+        // Search
+        if ($request->has('search') && $request->search) {
+            $query->where(function ($q) use ($request) {
+                $q->where('name', 'like', '%' . $request->search . '%')
+                  ->orWhere('email', 'like', '%' . $request->search . '%');
+            });
+        }
+
+        // Sort
+        $sortBy = $request->get('sort_by', 'created_at');
+        $sortOrder = $request->get('sort_order', 'desc');
+        $query->orderBy($sortBy, $sortOrder);
+
+        $users = $query->paginate(20)->withQueryString();
+
+        return view('admin.users.index', compact('users'));
+    }
+}