feat: add BrentPriceResource with 30-day line chart widget

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/Feature/Admin/BrentPriceResourceTest.php

@@ -0,0 +1,22 @@
+<?php
+
+use App\Filament\Resources\BrentPriceResource\Pages\ListBrentPrices;
+use App\Models\BrentPrice;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    $this->admin = User::factory()->admin()->create();
+    $this->actingAs($this->admin);
+});
+
+it('renders the brent price list', function () {
+    $prices = BrentPrice::factory()->count(3)->create();
+
+    Livewire::test(ListBrentPrices::class)
+        ->assertOk()
+        ->assertCanSeeTableRecords($prices);
+});