CLI now installs and updates in China

CLI install and update downloads were blocked in mainland China because they were served from GitHub, which is unreachable behind the Great Firewall without a VPN.

• Mirrored every CLI release to a global edge network reachable from China
• Switched all binary downloads to that mirror so every client uses one fast, China-reachable path
• Verified the latest release is reachable in-region so existing installs keep updating without interruption