fix: update config import instructions to reflect TOML/QR flow

docs/gui-quickstart-windows.md

@@ -25,7 +25,10 @@ Windows will show a **UAC prompt** asking for administrator permission. This is
 
 ## 4. Load your config
 
-Your server administrator will provide a `client.toml` config file. On first launch, tap **Open config** and select the file.
+Your server administrator will provide either a `client.toml` config file or a QR code image.
+
+- **TOML file:** tap **Import from file** and select the `.toml` file.
+- **QR code:** tap **Import QR image** and select the QR code image file from disk.
 
 ## 5. Connect