feat: add BrentPriceResource with 30-day line chart widget

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

app/Filament/Widgets/BrentPriceChartWidget.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Filament\Widgets;
+
+use App\Models\BrentPrice;
+use Filament\Widgets\ChartWidget;
+
+class BrentPriceChartWidget extends ChartWidget
+{
+    protected ?string $heading = 'Brent Crude — Last 30 Days (USD/barrel)';
+
+    protected ?string $pollingInterval = null;
+
+    protected function getData(): array
+    {
+        $prices = BrentPrice::orderBy('date')
+            ->where('date', '>=', now()->subDays(30)->toDateString())
+            ->get();
+
+        return [
+            'datasets' => [
+                [
+                    'label' => 'USD/barrel',
+                    'data' => $prices->pluck('price_usd')->map(fn ($p) => (float) $p)->toArray(),
+                    'borderColor' => '#f59e0b',
+                    'fill' => false,
+                    'tension' => 0.3,
+                ],
+            ],
+            'labels' => $prices->pluck('date')
+                ->map(fn ($d) => $d->format('d M'))
+                ->toArray(),
+        ];
+    }
+
+    protected function getType(): string
+    {
+        return 'line';
+    }
+}