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>

crates/mtgc-core/src/sql/reference_schema.sql

@@ -12,7 +12,8 @@ CREATE TABLE IF NOT EXISTS oracle_cards (
     type_line      TEXT NOT NULL DEFAULT '',
     oracle_text    TEXT NOT NULL DEFAULT '',
     produced_mana      INTEGER NOT NULL DEFAULT 0,  -- WUBRG bitmask (lands/rocks/dorks)
-    produces_colorless INTEGER NOT NULL DEFAULT 0   -- boolean: can produce {C}
+    produces_colorless INTEGER NOT NULL DEFAULT 0,  -- boolean: can produce {C}
+    legalities         INTEGER NOT NULL DEFAULT 0   -- 2 bits/format x 8 formats, see model::LEGALITY_FORMATS
 );
 CREATE INDEX IF NOT EXISTS idx_oracle_name_lower ON oracle_cards(name_lower);
 CREATE INDEX IF NOT EXISTS idx_oracle_ci ON oracle_cards(color_identity);