Add Hermes Tweet skill

[kriptoburak]

Summary

• Add a hermes/hermes-tweet ecosystem skill for installing, validating, and safely operating the Hermes Tweet X/Twitter plugin.
• Document the new Hermes collection in the README catalog.

Validation

• git diff --check
• Frontmatter sanity check with Python
• Public link checks for the Hermes Tweet repo, PyPI package, and Hermes Agent repo

License note

This marketplace repo does not declare a root license; the submitted skill links to Hermes Tweet, which is MIT licensed upstream.