Extends POST /admin/import_viewer to accept owned_cards (snapshot full-replace). Unknown card_ids are skipped, counted in skipped_card_count on the response, and logged server-side. Count is clamped to OwnedCardEntry.MaxCopies (3). Also injects ILogger into AdminController and adds Cards/Items/Decks to the viewer reload graph. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>