fix: comprehensive UUID/username persistence bug fixes (#252)

* fix: comprehensive UUID/username persistence bug fixes

Major fixes for UUID/skin reset issues that caused players to lose cosmetics:

Core fixes:
- Username rename now preserves UUID (atomic rename, not new identity)
- Atomic config writes with backup/recovery system
- Case-insensitive UUID lookup with case-preserving storage
- Pre-launch validation blocks play if no username configured
- Removed saveUsername calls from launch/install flows

UUID Modal fixes:
- Fixed isCurrent badge showing on wrong user
- Added switch identity button to change between saved usernames
- Fixed custom UUID input using unsaved DOM username
- UUID list now refreshes when player name changes
- Enabled copy/paste in custom UUID input field

UI/UX improvements:
- Added translation keys for switch username functionality
- CSS user-select fix for UUID input fields
- Allowed Ctrl+V/C/X/A shortcuts in Electron

Files: config.js, gameLauncher.js, gameManager.js, playerManager.js,
launcher.js, settings.js, main.js, preload.js, style.css, en.json

See UUID_BUGS_FIX_PLAN.md for detailed bug list (18 bugs, 16 fixed)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(i18n): add switch username translations to all locales

Added translation keys for username switching functionality:
- notifications.noUsername
- notifications.switchUsernameSuccess
- notifications.switchUsernameFailed
- notifications.playerNameTooLong
- confirm.switchUsernameTitle
- confirm.switchUsernameMessage
- confirm.switchUsernameButton

Languages updated: de-DE, es-ES, fr-FR, id-ID, pl-PL, pt-BR, ru-RU, sv-SE, tr-TR

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: move UUID_BUGS_FIX_PLAN.md to docs folder

* docs: update UUID_BUGS_FIX_PLAN with complete fix details

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

GUI/locales/de-DE.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Mod konnte nicht gelöscht werden: {error}",
     "modsModNotFound": "Mod-Informationen nicht gefunden",
     "hwAccelSaved": "Hardware-Beschleunigungseinstellung gespeichert",
-    "hwAccelSaveFailed": "Hardware-Beschleunigungseinstellung konnte nicht gespeichert werden"
+    "hwAccelSaveFailed": "Hardware-Beschleunigungseinstellung konnte nicht gespeichert werden",
+    "noUsername": "Kein Benutzername konfiguriert. Bitte speichere zuerst deinen Benutzernamen.",
+    "switchUsernameSuccess": "Erfolgreich zu \"{username}\" gewechselt!",
+    "switchUsernameFailed": "Benutzername konnte nicht gewechselt werden",
+    "playerNameTooLong": "Spielername darf maximal 16 Zeichen haben"
   },
   "confirm": {
     "defaultTitle": "Aktion bestätigen",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Löschen",
     "uninstallGameTitle": "Spiel deinstallieren",
     "uninstallGameMessage": "Möchtest du Hytale wirklich deinstallieren? Alle Spieldateien werden gelöscht.",
-    "uninstallGameButton": "Deinstallieren"
+    "uninstallGameButton": "Deinstallieren",
+    "switchUsernameTitle": "Identität wechseln",
+    "switchUsernameMessage": "Zu Benutzername \"{username}\" wechseln? Dies ändert deine aktuelle Spieleridentität.",
+    "switchUsernameButton": "Wechseln"
   },
   "progress": {
     "initializing": "Initialisiere...",

GUI/locales/en.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Failed to delete mod: {error}",
     "modsModNotFound": "Mod information not found",
     "hwAccelSaved": "Hardware acceleration setting saved",
-    "hwAccelSaveFailed": "Failed to save hardware acceleration setting"
+    "hwAccelSaveFailed": "Failed to save hardware acceleration setting",
+    "noUsername": "No username configured. Please save your username first.",
+    "switchUsernameSuccess": "Switched to \"{username}\" successfully!",
+    "switchUsernameFailed": "Failed to switch username",
+    "playerNameTooLong": "Player name must be 16 characters or less"
   },
   "confirm": {
     "defaultTitle": "Confirm action",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Delete",
     "uninstallGameTitle": "Uninstall game",
     "uninstallGameMessage": "Are you sure you want to uninstall Hytale? All game files will be deleted.",
-    "uninstallGameButton": "Uninstall"
+    "uninstallGameButton": "Uninstall",
+    "switchUsernameTitle": "Switch Identity",
+    "switchUsernameMessage": "Switch to username \"{username}\"? This will change your current player identity.",
+    "switchUsernameButton": "Switch"
   },
   "progress": {
     "initializing": "Initializing...",

GUI/locales/es-ES.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Error al eliminar mod: {error}",
     "modsModNotFound": "Información del mod no encontrada",
     "hwAccelSaved": "Configuración de aceleración por hardware guardada",
-    "hwAccelSaveFailed": "Error al guardar la configuración de aceleración por hardware"
+    "hwAccelSaveFailed": "Error al guardar la configuración de aceleración por hardware",
+    "noUsername": "No hay nombre de usuario configurado. Por favor, guarda tu nombre de usuario primero.",
+    "switchUsernameSuccess": "¡Cambiado a \"{username}\" con éxito!",
+    "switchUsernameFailed": "Error al cambiar nombre de usuario",
+    "playerNameTooLong": "El nombre del jugador debe tener 16 caracteres o menos"
   },
   "confirm": {
     "defaultTitle": "Confirmar acción",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Eliminar",
     "uninstallGameTitle": "Desinstalar juego",
     "uninstallGameMessage": "¿Estás seguro de que quieres desinstalar Hytale? Se eliminarán todos los archivos del juego.",
-    "uninstallGameButton": "Desinstalar"
+    "uninstallGameButton": "Desinstalar",
+    "switchUsernameTitle": "Cambiar identidad",
+    "switchUsernameMessage": "¿Cambiar al nombre de usuario \"{username}\"? Esto cambiará tu identidad de jugador actual.",
+    "switchUsernameButton": "Cambiar"
   },
   "progress": {
     "initializing": "Inicializando...",

GUI/locales/fr-FR.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Échec de la suppression du mod: {error}",
     "modsModNotFound": "Informations du mod introuvables",
     "hwAccelSaved": "Paramètre d'accélération matérielle sauvegardé",
-    "hwAccelSaveFailed": "Échec de la sauvegarde du paramètre d'accélération matérielle"
+    "hwAccelSaveFailed": "Échec de la sauvegarde du paramètre d'accélération matérielle",
+    "noUsername": "Aucun nom d'utilisateur configuré. Veuillez d'abord enregistrer votre nom d'utilisateur.",
+    "switchUsernameSuccess": "Basculé vers \"{username}\" avec succès!",
+    "switchUsernameFailed": "Échec du changement de nom d'utilisateur",
+    "playerNameTooLong": "Le nom du joueur doit comporter 16 caractères ou moins"
   },
   "confirm": {
     "defaultTitle": "Confirmer l'action",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Supprimer",
     "uninstallGameTitle": "Désinstaller le jeu",
     "uninstallGameMessage": "Êtes-vous sûr de vouloir désinstaller Hytale? Tous les fichiers du jeu seront supprimés.",
-    "uninstallGameButton": "Désinstaller"
+    "uninstallGameButton": "Désinstaller",
+    "switchUsernameTitle": "Changer d'identité",
+    "switchUsernameMessage": "Basculer vers le nom d'utilisateur \"{username}\"? Cela changera votre identité de joueur actuelle.",
+    "switchUsernameButton": "Changer"
   },
   "progress": {
     "initializing": "Initialisation...",

GUI/locales/id-ID.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Gagal menghapus mod: {error}",
     "modsModNotFound": "Informasi mod tidak ditemukan",
     "hwAccelSaved": "Pengaturan akselerasi perangkat keras disimpan",
-    "hwAccelSaveFailed": "Gagal menyimpan pengaturan akselerasi perangkat keras"
+    "hwAccelSaveFailed": "Gagal menyimpan pengaturan akselerasi perangkat keras",
+    "noUsername": "Nama pengguna belum dikonfigurasi. Silakan simpan nama pengguna terlebih dahulu.",
+    "switchUsernameSuccess": "Berhasil beralih ke \"{username}\"!",
+    "switchUsernameFailed": "Gagal beralih nama pengguna",
+    "playerNameTooLong": "Nama pemain harus 16 karakter atau kurang"
   },
   "confirm": {
     "defaultTitle": "Konfirmasi tindakan",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Hapus",
     "uninstallGameTitle": "Hapus instalasi game",
     "uninstallGameMessage": "Apakah kamu yakin ingin menghapus instalasi Hytale? Semua file game akan dihapus.",
-    "uninstallGameButton": "Hapus Instalasi"
+    "uninstallGameButton": "Hapus Instalasi",
+    "switchUsernameTitle": "Ganti Identitas",
+    "switchUsernameMessage": "Beralih ke nama pengguna \"{username}\"? Ini akan mengubah identitas pemain saat ini.",
+    "switchUsernameButton": "Ganti"
   },
   "progress": {
     "initializing": "Menginisialisasi...",

GUI/locales/pl-PL.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Nie udało się usunąć moda: {error}",
     "modsModNotFound": "Nie znaleziono informacji o modzie",
     "hwAccelSaved": "Zapisano ustawienie przyspieszenia sprzętowego",
-    "hwAccelSaveFailed": "Nie udało się zapisać ustawienia przyspieszenia sprzętowego"
+    "hwAccelSaveFailed": "Nie udało się zapisać ustawienia przyspieszenia sprzętowego",
+    "noUsername": "Nie skonfigurowano nazwy użytkownika. Najpierw zapisz swoją nazwę użytkownika.",
+    "switchUsernameSuccess": "Pomyślnie przełączono na \"{username}\"!",
+    "switchUsernameFailed": "Nie udało się przełączyć nazwy użytkownika",
+    "playerNameTooLong": "Nazwa gracza musi mieć 16 znaków lub mniej"
   },
   "confirm": {
     "defaultTitle": "Potwierdź działanie",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Usuń",
     "uninstallGameTitle": "Odinstaluj grę",
     "uninstallGameMessage": "Czy na pewno chcesz odinstalować Hytale? Wszystkie pliki gry zostaną usunięte.",
-    "uninstallGameButton": "Odinstaluj"
+    "uninstallGameButton": "Odinstaluj",
+    "switchUsernameTitle": "Zmień tożsamość",
+    "switchUsernameMessage": "Przełączyć na nazwę użytkownika \"{username}\"? To zmieni Twoją aktualną tożsamość gracza.",
+    "switchUsernameButton": "Przełącz"
   },
   "progress": {
     "initializing": "Inicjalizacja...",

GUI/locales/pt-BR.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Falha ao excluir mod: {error}",
     "modsModNotFound": "Informações do mod não encontradas",
     "hwAccelSaved": "Configuração de aceleração de hardware salva",
-    "hwAccelSaveFailed": "Falha ao salvar configuração de aceleração de hardware"
+    "hwAccelSaveFailed": "Falha ao salvar configuração de aceleração de hardware",
+    "noUsername": "Nenhum nome de usuário configurado. Por favor, salve seu nome de usuário primeiro.",
+    "switchUsernameSuccess": "Alterado para \"{username}\" com sucesso!",
+    "switchUsernameFailed": "Falha ao trocar nome de usuário",
+    "playerNameTooLong": "O nome do jogador deve ter 16 caracteres ou menos"
   },
   "confirm": {
     "defaultTitle": "Confirmar ação",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Excluir",
     "uninstallGameTitle": "Desinstalar jogo",
     "uninstallGameMessage": "Tem certeza de que deseja desinstalar Hytale? Todos os arquivos do jogo serão excluídos.",
-    "uninstallGameButton": "Desinstalar"
+    "uninstallGameButton": "Desinstalar",
+    "switchUsernameTitle": "Trocar Identidade",
+    "switchUsernameMessage": "Trocar para o nome de usuário \"{username}\"? Isso mudará sua identidade de jogador atual.",
+    "switchUsernameButton": "Trocar"
   },
   "progress": {
     "initializing": "Inicializando...",

GUI/locales/ru-RU.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Не получилось удалить мод: {error}",
     "modsModNotFound": "Информация по моду не найдена",
     "hwAccelSaved": "Настройка аппаратного ускорения сохранена!",
-    "hwAccelSaveFailed": "Не удалось сохранить настройку аппаратного ускорения"
+    "hwAccelSaveFailed": "Не удалось сохранить настройку аппаратного ускорения",
+    "noUsername": "Имя пользователя не настроено. Пожалуйста, сначала сохраните имя пользователя.",
+    "switchUsernameSuccess": "Успешно переключено на \"{username}\"!",
+    "switchUsernameFailed": "Не удалось переключить имя пользователя",
+    "playerNameTooLong": "Имя игрока должно быть не более 16 символов"
   },
   "confirm": {
     "defaultTitle": "Подтвердить действие",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Удалить",
     "uninstallGameTitle": "Удалить игру",
     "uninstallGameMessage": "Вы уверены, что хотите удалить Hytale? Все данные игры будут безвозвратно удалены!",
-    "uninstallGameButton": "Удалить"
+    "uninstallGameButton": "Удалить",
+    "switchUsernameTitle": "Сменить личность",
+    "switchUsernameMessage": "Переключиться на имя пользователя \"{username}\"? Это изменит вашу текущую личность игрока.",
+    "switchUsernameButton": "Переключить"
   },
   "progress": {
     "initializing": "Инициализация...",

GUI/locales/sv-SE.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Misslyckades med att ta bort modd: {error}",
     "modsModNotFound": "Moddinformation hittades inte",
     "hwAccelSaved": "Hårdvaruaccelerationsinställning sparad",
-    "hwAccelSaveFailed": "Misslyckades med att spara hårdvaruaccelerationsinställning"
+    "hwAccelSaveFailed": "Misslyckades med att spara hårdvaruaccelerationsinställning",
+    "noUsername": "Inget användarnamn konfigurerat. Vänligen spara ditt användarnamn först.",
+    "switchUsernameSuccess": "Bytte till \"{username}\" framgångsrikt!",
+    "switchUsernameFailed": "Misslyckades med att byta användarnamn",
+    "playerNameTooLong": "Spelarnamnet måste vara 16 tecken eller mindre"
   },
   "confirm": {
     "defaultTitle": "Bekräfta åtgärd",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Ta bort",
     "uninstallGameTitle": "Avinstallera spel",
     "uninstallGameMessage": "Är du säker på att du vill avinstallera Hytale? Alla spelfiler kommer att tas bort.",
-    "uninstallGameButton": "Avinstallera"
+    "uninstallGameButton": "Avinstallera",
+    "switchUsernameTitle": "Byt identitet",
+    "switchUsernameMessage": "Byta till användarnamn \"{username}\"? Detta kommer att ändra din nuvarande spelaridentitet.",
+    "switchUsernameButton": "Byt"
   },
   "progress": {
     "initializing": "Initierar...",

GUI/locales/tr-TR.json

@@ -211,7 +211,11 @@
     "modsDeleteFailed": "Mod silinemedi: {error}",
     "modsModNotFound": "Mod bilgileri bulunamadı",
     "hwAccelSaved": "Donanım hızlandırma ayarı kaydedildi",
-    "hwAccelSaveFailed": "Donanım hızlandırma ayarı kaydedilemedi"
+    "hwAccelSaveFailed": "Donanım hızlandırma ayarı kaydedilemedi",
+    "noUsername": "Kullanıcı adı yapılandırılmadı. Lütfen önce kullanıcı adınızı kaydedin.",
+    "switchUsernameSuccess": "\"{username}\" adına başarıyla geçildi!",
+    "switchUsernameFailed": "Kullanıcı adı değiştirilemedi",
+    "playerNameTooLong": "Oyuncu adı 16 karakter veya daha az olmalıdır"
   },
   "confirm": {
     "defaultTitle": "Eylemi onayla",
@@ -226,7 +230,10 @@
     "deleteUuidButton": "Sil",
     "uninstallGameTitle": "Oyunu kaldır",
     "uninstallGameMessage": "Hytale'yi kaldırmak istediğinizden emin misiniz? Tüm oyun dosyaları silinecektir.",
-    "uninstallGameButton": "Kaldır"
+    "uninstallGameButton": "Kaldır",
+    "switchUsernameTitle": "Kimlik Değiştir",
+    "switchUsernameMessage": "\"{username}\" kullanıcı adına geçilsin mi? Bu mevcut oyuncu kimliğinizi değiştirecektir.",
+    "switchUsernameButton": "Değiştir"
   },
   "progress": {
     "initializing": "Başlatılıyor...",