d012d40b18
Fixes #1168. articles.currency exists in the DB and REST API, but the staged-operation schemas and the two MCP tools had no currency param, so agent-created articles were always SEK and an agent asked to create an EUR-priced article could not. - CreateArticleParamsSchema/UpdateArticleParamsSchema accept an optional ISO 4217 code (normalized to upper case; empty/null = unset). The currencies-table FK stays the allow-list: a 23503 on the currency FK maps to a clear 400 instead of a raw 500. - commitCreateArticle inserts currency ?? 'SEK'; the sparse update executor passes it through only when staged. - gnubok_create_article / gnubok_update_article expose the param. Co-authored-by: Claude Fable 5 <noreply@anthropic.com>