feat: add fullscreen QR code for subscription connection

- New ConnectionQR page with fullscreen QR display (no modal)
- QR button in InstallationGuide header next to platform selector
- Respects hideLink setting: shows URL below QR only when visible
- i18n translations for ru, en, zh, fa

src/locales/en.json

@@ -422,7 +422,10 @@
       "notConfigured": "Connection methods are not configured yet",
       "notConfiguredUser": "Connection setup is in progress. Please check back later.",
       "notConfiguredAdmin": "No connection apps have been configured. Set them up in the Apps settings.",
-      "goToApps": "Go to Apps settings"
+      "goToApps": "Go to Apps settings",
+      "qrTitle": "Subscription QR Code",
+      "qrScanHint": "Scan to connect",
+      "qrButton": "QR Code"
     },
     "myDevices": "My Devices",
     "noDevices": "No connected devices",

src/locales/fa.json

@@ -327,7 +327,10 @@
       "notConfigured": "روش‌های اتصال هنوز پیکربندی نشده‌اند",
       "notConfiguredUser": "تنظیمات اتصال در حال انجام است. لطفاً بعداً مراجعه کنید.",
       "notConfiguredAdmin": "هیچ برنامه اتصالی پیکربندی نشده است. آن‌ها را در تنظیمات برنامه‌ها تنظیم کنید.",
-      "goToApps": "رفتن به تنظیمات برنامه‌ها"
+      "goToApps": "رفتن به تنظیمات برنامه‌ها",
+      "qrTitle": "کد QR اشتراک",
+      "qrScanHint": "برای اتصال با دوربین اسکن کنید",
+      "qrButton": "کد QR"
     },
     "additionalOptions": {
       "title": "گزینه‌های اضافی",

src/locales/ru.json

@@ -445,7 +445,10 @@
       "notConfigured": "Способы подключения ещё не настроены",
       "notConfiguredUser": "Настройка подключения в процессе. Пожалуйста, загляните позже.",
       "notConfiguredAdmin": "Приложения для подключения не настроены. Настройте их в разделе Приложения.",
-      "goToApps": "Перейти к настройке приложений"
+      "goToApps": "Перейти к настройке приложений",
+      "qrTitle": "QR-код подписки",
+      "qrScanHint": "Отсканируйте для подключения",
+      "qrButton": "QR-код"
     },
     "myDevices": "Мои устройства",
     "noDevices": "Нет подключенных устройств",

src/locales/zh.json

@@ -327,7 +327,10 @@
       "notConfigured": "连接方式尚未配置",
       "notConfiguredUser": "连接设置正在进行中，请稍后再来查看。",
       "notConfiguredAdmin": "尚未配置连接应用。请在应用设置中进行配置。",
-      "goToApps": "前往应用设置"
+      "goToApps": "前往应用设置",
+      "qrTitle": "订阅二维码",
+      "qrScanHint": "使用相机扫描以连接",
+      "qrButton": "二维码"
     },
     "additionalOptions": {
       "title": "附加选项",