ANU-23: Python Repository-change Workflow

This change adopts the Product Main-owned repository-change workflow in the Anuva Python Server without changing worker, protocol, simulator, security, or operator behavior.

• Implementation Plan
• Implementation Log
• Completion Report
• Linear: ANU-23
• Product Main source: docs/changes/2026-07-28-anu-19-repository-change-workflow/index.md
• Product Main review preview: https://main1.girishd.com/changes/2026-07-28-anu-19-repository-change-workflow/
• Draft PR: Shoonya-Game-Technologies/anuva-python-server#19
• Status: acceptance review complete; awaiting explicit completion approval for the linked draft PR