Flashcards: define public deck sharing scope

[AliBenrami]

Parent

Part of #41.

What to build

Define the product and UX scope for future public flashcards before implementation starts. The parent issue mentions public decks as a future extension, so this ticket should settle what publishing, viewing, and reusing decks should mean for TaskMaster.

Acceptance criteria

• Decide whether public decks are in scope for the first flashcard redesign release or should remain a later phase.
• Define what users can do with public decks: view only, copy/reuse, edit their own copy, or another model.
• Define the minimum deck metadata needed for public discovery and attribution.
• Identify privacy and deletion expectations for publishing and unpublishing a deck.
• Capture the agreed scope in follow-up implementation tickets if public decks move forward.

Blocked by

• Flashcards: split deck management into a focused My Flashcards page #42