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>

database/factories/WatchedEventFactory.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace Database\Factories;
+
+use App\Models\WatchedEvent;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/** @extends Factory<WatchedEvent> */
+class WatchedEventFactory extends Factory
+{
+    public function definition(): array
+    {
+        $startsAt = fake()->dateTimeBetween('-30 days', '+30 days');
+        $endsAt = (clone $startsAt)->modify('+'.fake()->numberBetween(1, 14).' days');
+
+        return [
+            'label' => fake()->sentence(3),
+            'starts_at' => $startsAt,
+            'ends_at' => $endsAt,
+            'notes' => fake()->boolean() ? fake()->paragraph() : null,
+        ];
+    }
+
+    public function active(): static
+    {
+        return $this->state([
+            'starts_at' => now()->subDays(2),
+            'ends_at' => now()->addDays(2),
+        ]);
+    }
+
+    public function inactive(): static
+    {
+        return $this->state([
+            'starts_at' => now()->subDays(30),
+            'ends_at' => now()->subDays(15),
+        ]);
+    }
+}