why: release LLM-friendly documentation outputs and CI fixes.

what:
- sphinx-gp-llms: llms.txt, llms-full.txt, docs.json, per-page .md
- Footer links all machine-readable formats
- autoconfigvalues :exclude: option
- Root sdist excludes gp-furo-theme Vite artifacts
- Bump all workspace packages 0.0.1a23 → 0.0.1a24
- CHANGES dated 2026-05-25, next unreleased is 0.0.1a25