[Client] Show localized card names, texts and pictures

Localization wiring now runs end to end: the oracle importer collects
foreignData for the configured language and the client renders it.

- [Oracle] Import localized names and rules texts for the selected cardLang
  - single-face cards store their foreignData name and full text
  - multi-face (split/adventure/aftermath/prepare) cards collect the joined
    name once and join each face's translated text with the same separator
    as the English merge; an incomplete translation falls back to English;
    the joined text follows the same highest-priority-set policy as the
    single-face path and is only collected when localization is enabled
  - the wizard switching languages re-imports the card database

- [Client] Display localized card info throughout the client
  - card info text/picture widgets and the game board re-render on language
    change
  - pictures resolve cardLang art through Scryfall's named endpoint using the
    localized name, falling back to id-based art when no match exists
  - deck editor keeps canonical English names as card identity (EditRole)
    while showing localized names (DisplayRole), so decks and wire names
    stay stable

- [Card] Add CardLocalization-backed name/text lookup and cards.xml v4
  localization elements with a bounded-size translation cache

- [Tests] Cover oracle foreignData import (incl. multi-face joins, priority
  and fallback paths), XML v4 localization parsing, deck model localized
  display and the language-aware settings default

Existing installations need to re-run Oracle to see translations: localized
data only lands in cards.xml when the Oracle app is started with the
preferred language selected — launch the separate "Oracle" program that
ships with Cockatrice, pick the language in the wizard and let it re-import
the card database.

The client's database cache (cards.xml.cache) is invalidated by the cache
format bump and the source-hash checks, but a cache written before the
re-import can still hold English-only entries (the hash uses file size and
mtime, so a same-size/same-timestamp rewrite may be served as-is); delete
cards.xml.cache and relaunch if no localized names/texts show up after
re-importing.

tests/settings/settings_defaults_test.cpp

@@ -549,6 +549,19 @@ TEST_F(SettingsDefaultsTest, CardsDisplay_ArrowDrawAnimation_Default)
     ASSERT_EQ(s.getArrowDrawAnimation(), true);
 }
 
+TEST_F(SettingsDefaultsTest, CardsDisplay_CardLang_Default)
+{
+    CardsDisplaySettings s(settingsPath, nullptr);
+    ASSERT_EQ(s.getCardLang(), QString("en"));
+}
+
+TEST_F(SettingsDefaultsTest, CardsDisplay_CardLang_SetAndGet)
+{
+    CardsDisplaySettings s(settingsPath, nullptr);
+    s.setCardLang("de");
+    ASSERT_EQ(s.getCardLang(), QString("de"));
+}
+
 // --- VisualDeckStorageSettings ---
 
 TEST_F(SettingsDefaultsTest, VisualDeckStorage_SortingOrder_Default)