Retain tab color when duplicating a tab

### Description of the new feature

When duplicating a tab, it would be great if the new tab would maintain the tab color of the tab it is duplicating, similar to how it maintains the folder of the duplicated tab.

For bonus credit, it could be an option: Retain tab color when duplicating a tab

### Proposed technical implementation details

_No response_

The issue names no files or tests, so start by locating the tab-duplication entry point and tracing how the source tab's folder and color are represented. Compare that path with existing tab-color handling, then verify that duplicating a colored tab preserves its color and, if implemented, that the behavior can be controlled by the proposed option.

Written by the indexing model from the issue text.