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/Models/RateLimit.php

@@ -0,0 +1,74 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class RateLimit extends Model
+{
+    protected $fillable = [
+        'user_id',
+        'requests_per_minute',
+        'requests_per_hour',
+        'requests_per_day',
+        'current_minute_count',
+        'current_hour_count',
+        'current_day_count',
+        'minute_started_at',
+        'hour_started_at',
+        'day_started_at',
+        'is_rate_limited',
+        'rate_limit_expires_at',
+    ];
+
+    protected $casts = [
+        'requests_per_minute' => 'integer',
+        'requests_per_hour' => 'integer',
+        'requests_per_day' => 'integer',
+        'current_minute_count' => 'integer',
+        'current_hour_count' => 'integer',
+        'current_day_count' => 'integer',
+        'minute_started_at' => 'datetime',
+        'hour_started_at' => 'datetime',
+        'day_started_at' => 'datetime',
+        'is_rate_limited' => 'boolean',
+        'rate_limit_expires_at' => 'datetime',
+    ];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function isMinuteLimitExceeded(): bool
+    {
+        if ($this->minute_started_at->lt(now()->subMinute())) {
+            return false; // Period expired, should be reset
+        }
+        return $this->current_minute_count >= $this->requests_per_minute;
+    }
+
+    public function isHourLimitExceeded(): bool
+    {
+        if ($this->hour_started_at->lt(now()->subHour())) {
+            return false; // Period expired, should be reset
+        }
+        return $this->current_hour_count >= $this->requests_per_hour;
+    }
+
+    public function isDayLimitExceeded(): bool
+    {
+        if ($this->day_started_at->lt(now()->subDay())) {
+            return false; // Period expired, should be reset
+        }
+        return $this->current_day_count >= $this->requests_per_day;
+    }
+
+    public function isAnyLimitExceeded(): bool
+    {
+        return $this->isMinuteLimitExceeded() 
+            || $this->isHourLimitExceeded() 
+            || $this->isDayLimitExceeded();
+    }
+}