feat(admin): add Filament resources for the forecasting stack

Adds three resources under a new "Forecasting" navigation group: a full-CRUD
WatchedEventResource for the Layer 5 volatility detector, plus read-only
WeeklyForecastResource and BacktestResource so the ridge model output and
its calibration can be inspected without SQL.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Filament/Resources/Backtests/Pages/ViewBacktest.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Filament\Resources\Backtests\Pages;
+
+use App\Filament\Resources\Backtests\BacktestResource;
+use Filament\Resources\Pages\ViewRecord;
+
+class ViewBacktest extends ViewRecord
+{
+    protected static string $resource = BacktestResource::class;
+
+    protected function getHeaderActions(): array
+    {
+        return [];
+    }
+}