Show error dialog for invalid URLs in GUI

Replaces status label updates with QMessageBox warnings for invalid video URLs in the main UI. Adds 'error_title' translation key to all supported languages for consistent error dialog titles.

languages/ar.json

@@ -288,6 +288,7 @@
     "all_selected": "تم تحديد الكل",
     "select_videos_all": "اختر الفيديوهات... (تم تحديد الكل)",
     "please_enter_url": "الرجاء إدخال رابط أولاً",
+    "error_title": "خطأ",
     "cookie_file_selected_title": "تم تحديد ملف الكوكيز",
     "cookie_file_selected_message": "ملف الكوكيز المحدد: {path}",
     "browser_cookies_selected_title": "تم تحديد كوكيز المتصفح",

languages/de.json

@@ -288,6 +288,7 @@
     "all_selected": "Alle ausgewählt",
     "select_videos_all": "Videos auswählen... (Alle ausgewählt)",
     "please_enter_url": "Bitte geben Sie zuerst eine URL ein",
+    "error_title": "Fehler",
     "cookie_file_selected_title": "Cookie-Datei ausgewählt",
     "cookie_file_selected_message": "Cookie-Datei ausgewählt: {path}",
     "browser_cookies_selected_title": "Browser-Cookies ausgewählt",

languages/en.json

@@ -288,6 +288,7 @@
     "all_selected": "All selected",
     "select_videos_all": "Select Videos... (All selected)",
     "please_enter_url": "Please enter a URL first",
+    "error_title": "Error",
     "cookie_file_selected_title": "Cookie File Selected",
     "cookie_file_selected_message": "Cookie file selected: {path}",
     "browser_cookies_selected_title": "Browser Cookies Selected",

languages/es.json

@@ -271,6 +271,7 @@
     "all_selected": "Todos seleccionados",
     "select_videos_all": "Seleccionar Videos... (Todos seleccionados)",
     "please_enter_url": "Por favor ingresa primero una URL",
+    "error_title": "Error",
     "cookie_file_selected_title": "Archivo de Cookies Seleccionado",
     "cookie_file_selected_message": "Archivo de cookies seleccionado: {path}",
     "browser_cookies_selected_title": "Cookies de Navegador Seleccionadas",

languages/fr.json

@@ -288,6 +288,7 @@
     "all_selected": "Tous sélectionnés",
     "select_videos_all": "Sélectionner les vidéos... (Tous sélectionnés)",
     "please_enter_url": "Veuillez d'abord entrer une URL",
+    "error_title": "Erreur",
     "cookie_file_selected_title": "Fichier de cookies sélectionné",
     "cookie_file_selected_message": "Fichier de cookies sélectionné : {path}",
     "browser_cookies_selected_title": "Cookies de navigateur sélectionnés",

languages/hi.json

@@ -288,6 +288,7 @@
     "all_selected": "सभी चुने गए",
     "select_videos_all": "वीडियो चुनें... (सभी चुने गए)",
     "please_enter_url": "कृपया पहले URL दर्ज करें",
+    "error_title": "त्रुटि",
     "cookie_file_selected_title": "कुकी फ़ाइल चुनी गई",
     "cookie_file_selected_message": "कुकी फ़ाइल चुनी गई: {path}",
     "browser_cookies_selected_title": "ब्राउज़र कुकीज़ चुनी गईं",

languages/id.json

@@ -288,6 +288,7 @@
     "all_selected": "Semua dipilih",
     "select_videos_all": "Pilih video... (Semua dipilih)",
     "please_enter_url": "Silakan masukkan URL terlebih dahulu",
+    "error_title": "Kesalahan",
     "cookie_file_selected_title": "File cookie dipilih",
     "cookie_file_selected_message": "File cookie dipilih: {path}",
     "browser_cookies_selected_title": "Cookies browser dipilih",

languages/it.json

@@ -288,6 +288,7 @@
     "all_selected": "Tutti selezionati",
     "select_videos_all": "Seleziona video... (Tutti selezionati)",
     "please_enter_url": "Inserisci prima un URL",
+    "error_title": "Errore",
     "cookie_file_selected_title": "File cookie selezionato",
     "cookie_file_selected_message": "File cookie selezionato: {path}",
     "browser_cookies_selected_title": "Cookie browser selezionati",

languages/ja.json

@@ -288,6 +288,7 @@
     "all_selected": "すべて選択済み",
     "select_videos_all": "動画を選択... (すべて選択済み)",
     "please_enter_url": "最初にURLを入力してください",
+    "error_title": "エラー",
     "cookie_file_selected_title": "Cookieファイルが選択されました",
     "cookie_file_selected_message": "選択されたCookieファイル: {path}",
     "browser_cookies_selected_title": "ブラウザCookieが選択されました",

languages/pl.json

@@ -288,6 +288,7 @@
     "all_selected": "Wszystkie wybrane",
     "select_videos_all": "Wybierz wideo... (Wszystkie wybrane)",
     "please_enter_url": "Proszę najpierw wprowadzić URL",
+    "error_title": "Błąd",
     "cookie_file_selected_title": "Wybrano plik ciasteczek",
     "cookie_file_selected_message": "Wybrano plik ciasteczek: {path}",
     "browser_cookies_selected_title": "Wybrano ciasteczka przeglądarki",

languages/pt.json

@@ -288,6 +288,7 @@
     "all_selected": "Todas selecionadas",
     "select_videos_all": "Selecionar Vídeos... (Todas selecionadas)",
     "please_enter_url": "Por favor, digite uma URL primeiro",
+    "error_title": "Erro",
     "cookie_file_selected_title": "Arquivo de Cookies Selecionado",
     "cookie_file_selected_message": "Arquivo de cookies selecionado: {path}",
     "browser_cookies_selected_title": "Cookies do Navegador Selecionados",

languages/ru.json

@@ -288,6 +288,7 @@
     "all_selected": "Все выбраны",
     "select_videos_all": "Выбрать видео... (Все выбраны)",
     "please_enter_url": "Пожалуйста, введите URL сначала",
+    "error_title": "Ошибка",
     "cookie_file_selected_title": "Файл Cookie выбран",
     "cookie_file_selected_message": "Файл cookie выбран: {path}",
     "browser_cookies_selected_title": "Cookie браузера выбраны",

languages/tr.json

@@ -288,6 +288,7 @@
     "all_selected": "Tümü seçildi",
     "select_videos_all": "Video seç... (Tümü seçildi)",
     "please_enter_url": "Lütfen önce bir URL girin",
+    "error_title": "Hata",
     "cookie_file_selected_title": "Çerez dosyası seçildi",
     "cookie_file_selected_message": "Çerez dosyası seçildi: {path}",
     "browser_cookies_selected_title": "Tarayıcı çerezleri seçildi",

languages/zh.json

@@ -288,6 +288,7 @@
     "all_selected": "全部已选择",
     "select_videos_all": "选择视频...（全部已选择）",
     "please_enter_url": "请先输入网址",
+    "error_title": "错误",
     "cookie_file_selected_title": "已选择 Cookie 文件",
     "cookie_file_selected_message": "已选择 Cookie 文件：{path}",
     "browser_cookies_selected_title": "已选择浏览器 Cookie",