Add Hermes Tweet cursor rule

[kriptoburak]

Summary

• Add a hermes-tweet library entry to rules.json.
• Add a Cursor MDC rule for using Hermes Tweet as the Hermes Agent X/Twitter plugin.
• Cover read-first workflows, environment-based credentials, action gating, and missing-tool troubleshooting.

Validation

• python3 -m json.tool rules.json
• git diff --check
• curl -fsSI https://github.com/Xquik-dev/hermes-tweet#readme
• curl -fsSI https://github.com/Xquik-dev/hermes-tweet/blob/master/.claude-plugin/plugin.json