Add recipient email and milestone notifications on transfer create.

Recipients can be emailed the download link immediately and at optional
reminders (7/3/1 days before unavailable, or when grace period starts).

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

app/Models/Transfer.php

@@ -23,6 +23,9 @@ class Transfer extends Model
         'qr_code_id',
         'title',
         'message',
+        'recipient_email',
+        'recipient_email_milestones',
+        'recipient_milestones_sent',
         'password_hash',
         'retention_days',
         'expires_at',
@@ -40,6 +43,8 @@ class Transfer extends Model
         'paid_until' => 'datetime',
         'grace_ends_at' => 'datetime',
         'last_billed_at' => 'datetime',
+        'recipient_email_milestones' => 'array',
+        'recipient_milestones_sent' => 'array',
         'downloads_total' => 'integer',
         'storage_bytes' => 'integer',
     ];
@@ -149,4 +154,24 @@ class Transfer extends Model
                     ->orWhere('grace_ends_at', '>', now());
             });
     }
+
+    public function wantsRecipientMilestone(string $milestone): bool
+    {
+        return in_array($milestone, (array) ($this->recipient_email_milestones ?? []), true);
+    }
+
+    public function recipientMilestoneSent(string $milestone): bool
+    {
+        return in_array($milestone, (array) ($this->recipient_milestones_sent ?? []), true);
+    }
+
+    public function markRecipientMilestoneSent(string $milestone): void
+    {
+        $sent = (array) ($this->recipient_milestones_sent ?? []);
+        $sent[] = $milestone;
+
+        $this->forceFill([
+            'recipient_milestones_sent' => array_values(array_unique($sent)),
+        ])->save();
+    }
 }