Copy Tags from One Board to Another in Deck

Description:
I would like to propose a new feature for NextCloud Deck that allows users to easily copy tags from one board to another within the Deck app. Often, users may create a set of tags for one board and wish to use the same set of tags in another board. This feature would streamline the process of maintaining consistent tags across multiple boards.

Implementation:
Introduce a new option in the Deck app that allows users to copy tags from one board to another. This feature should include the ability to select specific tags or copy all tags from the source board to the destination board.

Benefits:
Time-saving: Users can avoid manually recreating tags for each board, saving time and effort.
Consistency: Ensures consistency in tag usage across multiple boards, reducing the risk of inconsistencies or duplicates.

Additional Information:
If there are any concerns or considerations about this feature, please feel free to discuss them in the comments section. I believe this functionality would enhance the user experience and make Deck even more versatile for managing tasks across different boards.

Thank you for considering this feature request!

The issue names no files, tests, or entry points. Start by tracing how Deck boards and tags are created and managed, then determine where a source-board tag selection and destination-board copy flow belongs. Done means users can copy selected or all tags between boards without unintended duplicates, with the behavior covered by appropriate tests.