Fix custom server reconnection and reconnect strategy

- Fix: CONNECT/RETRY_CONNECT always force-disconnect before reconnecting
  (prevents JOIN_ROOM going to official server when custom is selected)
- Add forceDisconnect() helper: clears socket, eventQueue, episodeLobby,
  expectedAcksCount, broadcast status, persists cleanup to storage
- Fix: save useCustomServer to storage on Join Room click (no race condition)
- Fix: trigger RETRY_CONNECT on server mode toggle and custom URL change
- Fix: show error when Custom selected but no URL entered (no silent fallback)
- Fix: button label changed to 'Join / Create Room' in all 6 locales
- Rewrite scheduleReconnect() for two-phase strategy:
  Phase 1 (aggressive): 500ms-5s backoff, max 20 attempts or 5 minutes
  Phase 2 (slow): retry every 5 minutes indefinitely, never give up
- Persist reconnectAttempts/reconnectStartTime/reconnectFailed to session storage
- Remove 'reconnect_failed' status; slow mode shows as 'reconnecting' with retry button
- Add scheduleReconnect() call on offline path to continue retry cycle

extension/locales/de.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Optionales Passwort, um den Raumzugang zu beschränken",
   "PLACEHOLDER_PASSWORD": "Raum-Passwort (optional)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Passwort für den Raum (leer lassen, wenn keines vorhanden)",
-  "BTN_JOIN_ROOM": "Raum beitreten",
+  "BTN_JOIN_ROOM": "Raum beitreten / erstellen",
   "BTN_JOIN_ROOM_TOOLTIP": "Mit dem Raum verbinden",
   "LABEL_PUBLIC_ROOMS": "Öffentliche Räume",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "Liste der öffentlich verfügbaren Räume auf diesem Server",

extension/locales/en.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Optional password to restrict room access",
   "PLACEHOLDER_PASSWORD": "Room Password (optional)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Password for the room (leave empty if none)",
-  "BTN_JOIN_ROOM": "Join Room",
+  "BTN_JOIN_ROOM": "Join / Create Room",
   "BTN_JOIN_ROOM_TOOLTIP": "Connect to the room",
   "LABEL_PUBLIC_ROOMS": "Public Rooms",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "List of publicly available rooms on this server",

extension/locales/es.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Contraseña opcional para restringir el acceso a la sala",
   "PLACEHOLDER_PASSWORD": "Contraseña de la sala (opcional)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Contraseña para la sala (dejar vacío si no hay)",
-  "BTN_JOIN_ROOM": "Unirse a la sala",
+  "BTN_JOIN_ROOM": "Unirse / Crear sala",
   "BTN_JOIN_ROOM_TOOLTIP": "Conectarse a la sala",
   "LABEL_PUBLIC_ROOMS": "Salas públicas",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "Lista de salas públicas disponibles en este servidor",

extension/locales/fr.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Mot de passe optionnel pour restreindre l'accès au salon",
   "PLACEHOLDER_PASSWORD": "Mot de passe du salon (optionnel)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Mot de passe du salon (laisser vide si aucun)",
-  "BTN_JOIN_ROOM": "Rejoindre le salon",
+  "BTN_JOIN_ROOM": "Rejoindre / Créer le salon",
   "BTN_JOIN_ROOM_TOOLTIP": "Se connecter au salon",
   "LABEL_PUBLIC_ROOMS": "Salons publics",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "Liste des salons publics disponibles sur ce serveur",

extension/locales/pt-BR.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Senha opcional para restringir o acesso à sala",
   "PLACEHOLDER_PASSWORD": "Senha da sala (opcional)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Senha para a sala (deixe em branco se não houver)",
-  "BTN_JOIN_ROOM": "Entrar na sala",
+  "BTN_JOIN_ROOM": "Entrar / Criar sala",
   "BTN_JOIN_ROOM_TOOLTIP": "Conectar à sala",
   "LABEL_PUBLIC_ROOMS": "Salas públicas",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "Lista de salas públicas disponíveis neste servidor",

extension/locales/ru.json

@@ -26,7 +26,7 @@
   "LABEL_PASSWORD_TOOLTIP": "Дополнительный пароль для ограничения доступа к комнате",
   "PLACEHOLDER_PASSWORD": "Пароль комнаты (опционально)",
   "PLACEHOLDER_PASSWORD_TOOLTIP": "Пароль от комнаты (оставьте пустым, если его нет)",
-  "BTN_JOIN_ROOM": "Войти в комнату",
+  "BTN_JOIN_ROOM": "Войти / Создать комнату",
   "BTN_JOIN_ROOM_TOOLTIP": "Подключиться к комнате",
   "LABEL_PUBLIC_ROOMS": "Публичные комнаты",
   "LABEL_PUBLIC_ROOMS_TOOLTIP": "Список публично доступных комнат на этом сервере",