fix(ai): type AiConsent datetime properties for static analysis

Larastan inferred accepted_at as string, failing the call to
lessThanOrEqualTo() in the follow-up command. Document the datetime-cast
properties with a @property block, matching the convention in other models.

app/Models/AiConsent.php

@@ -2,6 +2,7 @@
 
 namespace App\Models;
 
+use Carbon\Carbon;
 use Database\Factories\AiConsentFactory;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
@@ -9,6 +10,10 @@ use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
+/**
+ * @property Carbon $accepted_at
+ * @property ?Carbon $revoked_at
+ */
 class AiConsent extends Model
 {
     /** @use HasFactory<AiConsentFactory> */