Notify transfer owners when files enter grace period.

Send grace-entered and countdown emails to owners alongside recipient grace milestones so unpaid transfers get clear wallet top-up reminders before deletion.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Models/Transfer.php

@@ -26,6 +26,7 @@ class Transfer extends Model
         'recipient_email',
         'recipient_email_milestones',
         'recipient_milestones_sent',
+        'owner_milestones_sent',
         'password_hash',
         'retention_days',
         'expires_at',
@@ -45,6 +46,7 @@ class Transfer extends Model
         'last_billed_at' => 'datetime',
         'recipient_email_milestones' => 'array',
         'recipient_milestones_sent' => 'array',
+        'owner_milestones_sent' => 'array',
         'downloads_total' => 'integer',
         'storage_bytes' => 'integer',
     ];
@@ -174,4 +176,19 @@ class Transfer extends Model
             'recipient_milestones_sent' => array_values(array_unique($sent)),
         ])->save();
     }
+
+    public function ownerMilestoneSent(string $milestone): bool
+    {
+        return in_array($milestone, (array) ($this->owner_milestones_sent ?? []), true);
+    }
+
+    public function markOwnerMilestoneSent(string $milestone): void
+    {
+        $sent = (array) ($this->owner_milestones_sent ?? []);
+        $sent[] = $milestone;
+
+        $this->forceFill([
+            'owner_milestones_sent' => array_values(array_unique($sent)),
+        ])->save();
+    }
 }