Import/Export Compatibility

[DavidMiserak]

User Story:
As a user with existing flashcard collections,
I need to import and export cards in common formats
So that I can migrate my knowledge base between different systems.

Details and Assumptions:

• Support importing/exporting Anki packages (.apkg)
• Support plain text imports with common formats
• Preserve metadata when possible during import/export
• Handle batch operations for multiple cards

Acceptance Criteria:

Given I have an Anki package file
When I import it into GoCard
Then the cards should be converted to Markdown files with appropriate metadata

Given I have a collection of GoCard markdown files
When I export them to an Anki package
Then the resulting file should be importable into Anki

Given I perform an import operation
When there are conflicts or format issues
Then I should receive clear error messages and options to resolve issues