fix endpint and language selection and deletion

backend_model.py

@@ -4,6 +4,8 @@ from enum import Enum
 from pydantic import BaseModel, Field
 from typing import Optional, List
 
+ENDPOINTS = [f"endpoint{i}" for i in range(1, 4)]  # Predefined endpoints
+
 class AnnouncementStates(Enum):
     IDLE: str = "Ready"
     TRANSLATING: str = "Translating"
@@ -29,6 +31,7 @@ class AnnouncementProgress(BaseModel):
 
 class AnnouncementSystem:
     def __init__(self):
+        self.available_endpoints = ENDPOINTS
         self.current_process = AnnouncementProgress(
             details=AnnouncementDetails(
                 text="",