Fix transfer share links and redesign recipient download email.

Use transfer.ladill.com share URLs in notifications and APIs, add the email
logo, and show file details with a prominent download button.

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

app/Models/QrCode.php

@@ -86,6 +86,14 @@ class QrCode extends Model
         return self::publicBaseUrl() . '/q/' . $this->short_code;
     }
 
+    /** Direct link for emails and share UI — always on the Transfer app host. */
+    public function shareUrl(): string
+    {
+        $base = rtrim((string) config('app.url'), '/');
+
+        return $base . '/q/' . $this->short_code;
+    }
+
     /**
      * Base URL for public QR links. Always the short platform domain
      * (ladill.com) — never the signed-in account/product host — so printed