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/tests/Unit/Services/CostCalculatorTest.php

@@ -0,0 +1,105 @@
+<?php
+
+namespace Tests\Unit\Services;
+
+use Tests\TestCase;
+use App\Services\LLM\CostCalculator;
+use App\Models\ModelPricing;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+class CostCalculatorTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private CostCalculator $calculator;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->calculator = new CostCalculator();
+    }
+
+    public function test_calculates_cost_correctly(): void
+    {
+        ModelPricing::create([
+            'provider' => 'openai',
+            'model' => 'gpt-4o-mini',
+            'input_price_per_million' => 0.15,
+            'output_price_per_million' => 0.60,
+            'is_active' => true,
+            'effective_from' => now(),
+        ]);
+
+        Cache::flush();
+
+        $costs = $this->calculator->calculate('openai', 'gpt-4o-mini', 1000, 500);
+
+        // (1000/1M * 0.15) + (500/1M * 0.60) = 0.00015 + 0.0003 = 0.00045
+        $this->assertEquals(0.00015, $costs['prompt_cost']);
+        $this->assertEquals(0.0003, $costs['completion_cost']);
+        $this->assertEquals(0.00045, $costs['total_cost']);
+    }
+
+    public function test_returns_zero_cost_for_unknown_model(): void
+    {
+        Cache::flush();
+
+        $costs = $this->calculator->calculate('unknown', 'unknown-model', 1000, 500);
+
+        $this->assertEquals(0.0, $costs['prompt_cost']);
+        $this->assertEquals(0.0, $costs['completion_cost']);
+        $this->assertEquals(0.0, $costs['total_cost']);
+    }
+
+    public function test_uses_cache_for_pricing(): void
+    {
+        ModelPricing::create([
+            'provider' => 'anthropic',
+            'model' => 'claude-sonnet-4',
+            'input_price_per_million' => 3.00,
+            'output_price_per_million' => 15.00,
+            'is_active' => true,
+            'effective_from' => now(),
+        ]);
+
+        Cache::flush();
+
+        // First call - should query database
+        $costs1 = $this->calculator->calculate('anthropic', 'claude-sonnet-4', 1000, 500);
+
+        // Second call - should use cache
+        $costs2 = $this->calculator->calculate('anthropic', 'claude-sonnet-4', 1000, 500);
+
+        $this->assertEquals($costs1, $costs2);
+        $this->assertTrue(Cache::has('pricing:anthropic:claude-sonnet-4'));
+    }
+
+    public function test_estimate_cost(): void
+    {
+        ModelPricing::create([
+            'provider' => 'openai',
+            'model' => 'gpt-4o',
+            'input_price_per_million' => 2.50,
+            'output_price_per_million' => 10.00,
+            'is_active' => true,
+            'effective_from' => now(),
+        ]);
+
+        Cache::flush();
+
+        $estimatedCost = $this->calculator->estimateCost('openai', 'gpt-4o', 2000, 1000);
+
+        // (2000/1M * 2.50) + (1000/1M * 10.00) = 0.005 + 0.01 = 0.015
+        $this->assertEquals(0.015, $estimatedCost);
+    }
+
+    public function test_clear_cache(): void
+    {
+        Cache::put('pricing:test:model', 'test_data', 3600);
+
+        $this->calculator->clearCache('test', 'model');
+
+        $this->assertFalse(Cache::has('pricing:test:model'));
+    }
+}