bug: Add GATEWAY5_CONNECT_HOSTS to .env.example

[AutomateIP]

Description

Add missing GATEWAY5_CONNECT_HOSTS environment variable to .env.example.

Reproduction Steps

1. Inspect .env.example in the root directory.
2. Observe that GATEWAY5_CONNECT_HOSTS is missing from the list of standard variables.

Expected Behavior

.env.example should include all necessary environment variable definitions, including GATEWAY5_CONNECT_HOSTS.

Environment

• OS: N/A
• Version: Main
• Python/Node/Go Version (if applicable): N/A

Checklist

• I have checked existing issues to avoid duplicates
• I have provided a clear description of the issue
• I have included steps to reproduce (if applicable)
• I have included relevant environment details