latest -> v2.1.312

Alias release latest → v2.1.312.

This is a lightweight pointer release for installers.
It does not contain Claude binaries.

• Target mirrored release: https://github.com/cometzero/claude-code-installer/releases/tag/v2.1.312
• Upstream release: https://github.com/anthropics/claude-code/releases/tag/v2.1.312