Export/Import Deck Data

[acezard]

Description:
As a player, I want to export my deck data to a file and import it on another device, so I can transfer my progress without relying on server storage.

Acceptance Criteria:

• An option is available for the user to export their deck data as a JSON file.
• The exported JSON file includes all relevant data (deck names, victory logs, etc.).
• An option is available for the user to import a previously exported JSON file.
• On importing, the app correctly integrates the imported data with the current state (either merging or replacing, based on a clear user choice).
• Appropriate error handling is in place for corrupted or improperly formatted files.
• The user receives clear notifications of a successful export/import and error messages if the process fails.

Notes/Comments:

• Consider the best UX approach for handling merge vs. replace on import.
• Ensure that the UI is intuitive and accessible for both export and import actions.
• This feature serves as a workaround for the limitations of local storage on static apps.