Use GitHub release metadata for docs release string

[brianckeegan]

Motivation

• Replace the hard-coded Sphinx release in docs/conf.py with the GitHub release/tag when docs are built from a release event, falling back to GITHUB_REF_NAME and then to "0.1.0"; no skills were used.

Description

• Update docs/conf.py to import json, add a _get_release() helper that reads the GitHub event payload from GITHUB_EVENT_PATH and returns release.tag_name when available, otherwise returns GITHUB_REF_NAME or the default "0.1.0", and set release = _get_release().

Testing

• Ran python -m py_compile docs/conf.py which succeeded.

---

Codex Task