Add deck legality checking, deck/library import-export, and a command palette

Threads Scryfall's per-format legalities through the reference db and adds a
deck-page indicator (structural rules + banned/restricted lists) that lists
violation reasons inline. Decks and selected library cards can now be
exported to/imported from plain-text decklists, with best-effort name
resolution and a report of anything that didn't match. Also adds a shuffle-
and-draw sample hand modal, and an Alt+/ command palette for jumping to a
tab, deck, or card without leaving the keyboard.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -42,6 +42,10 @@ pub fn run() {
             commands::set_deck_card,
             commands::deck_contents,
             commands::card_decks,
+            commands::export_deck,
+            commands::import_deck,
+            commands::export_library_cards,
+            commands::import_library_cards,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");