[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/carddatabase/carddatabase_test.cpp

@@ -2,9 +2,14 @@
 #include "test_card_database_path_provider.h"
 
 #include "gtest/gtest.h"
+#include <QTemporaryDir>
+#include <libcockatrice/card/card_info.h>
+#include <libcockatrice/card/database/card_database_data.h>
+#include <libcockatrice/card/database/parser/cockatrice_xml_4.h>
+#include <libcockatrice/card/lazy_properties_hash.h>
+#include <libcockatrice/card/printing/printing_info.h>
 #include <libcockatrice/interfaces/noop_card_preference_provider.h>
 #include <libcockatrice/interfaces/noop_card_set_priority_controller.h>
-
 namespace
 {
 
@@ -33,6 +38,49 @@ TEST(CardDatabaseTest, LoadXml)
     ASSERT_EQ(0, db->query()->getAllMainCardTypes().size()) << "Types not empty after clear";
     ASSERT_EQ(NotLoaded, db->getLoadStatus()) << "Incorrect status after clear";
 }
+
+TEST(CardDatabaseTest, Xml4LocalizedDataRoundTrip)
+{
+    NoopCardSetPriorityController controller;
+    CardSetPtr set =
+        CardSet::newInstance(&controller, "TST", "Test Set", "expansion", QDate(), CardSet::PriorityPrimary);
+
+    QHash<QString, QString> props;
+    props["manacost"] = "1R";
+    PrintingInfo printing(set, LazyPropertiesHash(props));
+    SetToPrintingsMap setsInfo;
+    setsInfo["TST"].append(printing);
+
+    CardInfo::UiAttributes attributes = {.tableRow = 1};
+    CardInfoPtr card =
+        CardInfo::newInstance("Lightning Bolt", "Deal 3 damage.", false, {}, {}, {}, setsInfo, attributes);
+    card->setLocalizedName("de", "Blitzschlag");
+    card->setLocalizedText("de", "Blitzschlag fügt 3 Schadenspunkte zu.");
+
+    SetNameMap sets;
+    sets.insert("TST", set);
+    CardNameMap cards;
+    cards.insert("Lightning Bolt", card);
+
+    QTemporaryDir tempDir;
+    const QString fileName = tempDir.filePath("cards.xml");
+    NoopCardPreferenceProvider prefProvider;
+    CockatriceXml4Parser writer(&prefProvider, &controller);
+    ASSERT_TRUE(writer.saveToFile({}, sets, cards, fileName));
+
+    CardDatabaseData data;
+    CockatriceXml4Parser parser(&prefProvider, &controller);
+    QFile file(fileName);
+    ASSERT_TRUE(file.open(QIODevice::ReadOnly));
+    parser.parseFileInto(file, data);
+
+    CardInfoPtr loaded = data.cards.value("Lightning Bolt");
+    ASSERT_FALSE(loaded.isNull());
+    ASSERT_EQ(loaded->getName(), "Lightning Bolt");
+    ASSERT_EQ(loaded->getLocalizedName("de"), "Blitzschlag");
+    ASSERT_EQ(loaded->getLocalizedText("de"), "Blitzschlag fügt 3 Schadenspunkte zu.");
+    ASSERT_EQ(loaded->getLocalizedText("fr"), "Deal 3 damage.");
+}
 } // namespace
 
 int main(int argc, char **argv)