How-To: Document Template Engine

Demonstrates template CRUD with substitution and admin-gated writes. Field trial: FT197 (../NENE2-FT/templatelog/).

Pattern summary

• UNIQUE(name) constraint on templates → 409 on duplicate
• List endpoint excludes body to reduce payload
• POST /templates/{id}/render accepts vars object, substitutes placeholders
• Unknown variables left as-is (no error)
• Admin key gates create/update/delete; render is public