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/Models/WeeklyForecast.php

@@ -2,7 +2,9 @@
 
 namespace App\Models;
 
+use Database\Factories\WeeklyForecastFactory;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 
 #[Fillable([
@@ -17,6 +19,9 @@ use Illuminate\Database\Eloquent\Model;
 ])]
 class WeeklyForecast extends Model
 {
+    /** @use HasFactory<WeeklyForecastFactory> */
+    use HasFactory;
+
     protected function casts(): array
     {
         return [