docs: point HUMANS.md at the constitution's new core/ location
Why: holocron moved ai-constitution.md from docs/ to core/ so it deploys
with governance.md; the two path-qualified citations here would dangle.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
docs(humans): move human practitioner instructions to wiki
## Why
HUMANS.md belongs in the wiki — it's practitioner-facing reference
material, not a file agents need to read from the repo tree. Moving it
here makes it browsable via Gitea's wiki UI and removes it from the
main repo's docs/ directory.
Refs: Defame1297/holocron#15
