Add mock options in frontend and removed from environment variables

.env.example

@@ -5,9 +5,6 @@ ADMIN_PASSWORD=changeme123
 # JWT signing secret generate with: python -c "import secrets; print(secrets.token_hex(32))"
 SECRET_KEY=replace-with-a-random-64-char-hex-string
 
-# Set to true to skip real AVConnect calls (for testing)
-# MOCK_AVCONNECT=true
-
 # Port configuration
 APP_PORT=8000