Automate the vocabulary change workflow

[hwesterb]

Summary

• add one canonical verify_vocabulary_change.py command with explicit refresh and non-destructive check modes
• verify clean staging, database/export parity, generated manual/audit/root freshness, doc hash refs, all exported hashes, and deterministic reconstruction
• snapshot and restore generated outputs and vocabulary JSON so checks preserve uncommitted work
• isolate temporary rebuild registry writes from the developer home directory
• make Python 3.12 CI use the same command contributors run locally
• add repository-level AGENTS.md / CLAUDE.md guidance and correct the stale reverse-direction workflow in CONTRIBUTING.md

No vocabulary definitions, database, paper, typography, frontend, static assets, or deployment files change.

Verification

• canonical check workflow passed against all 453 patterns
• canonical refresh workflow passed
• 388 tests passed
• Ruff lint and format checks passed
• CI YAML parsed successfully
• authored commit uses henrik.westerberg@emergentwisdom.org