Deck chips open their deck

Deck-name chips in the Library, Card Search and the card preview modal are
now buttons (DeckChip) that open that deck in the Decks tab — on mobile,
straight to its building screen. App provides the open-deck callback via
context and hands the deck id to DeckView.

Closes #19

src/views/DeckView.tsx

@@ -427,7 +427,16 @@ function computeDeckLegality(deck: Deck | null | undefined, contents: DeckEntry[
  * card list, mana curve, and legality tile recompute immediately instead of
  * only on the next mount.
  */
-export function DeckView({ refreshSignal }: { refreshSignal?: number }) {
+export function DeckView({
+  refreshSignal,
+  openDeckId,
+  onOpenedDeck,
+}: {
+  refreshSignal?: number;
+  /** A deck to open, e.g. from a deck chip elsewhere; `onOpenedDeck` clears it. */
+  openDeckId?: number | null;
+  onOpenedDeck?: () => void;
+}) {
   const [decks, setDecks] = useState<Deck[]>([]);
   const [selected, setSelected] = usePersistedState<number | null>(libraryKey("deck-selected"), null);
   const [newName, setNewName] = useState("");
@@ -444,6 +453,14 @@ export function DeckView({ refreshSignal }: { refreshSignal?: number }) {
   // this only matters below the .deck-layout stacking breakpoint; CSS keeps
   // both panes visible side by side above it regardless of this flag.
   const [mobileShowList, setMobileShowList] = useState(true);
+
+  // Open a deck asked for from outside — straight to its building screen.
+  useEffect(() => {
+    if (openDeckId == null) return;
+    setSelected(openDeckId);
+    setMobileShowList(false);
+    onOpenedDeck?.();
+  }, [openDeckId]);
   // Android back from the deck-building screen returns to the deck list, like
   // its ← button. Only while they're separate screens (the ≤720px
   // `.deck-layout` breakpoint): side by side, flipping the flag changes