Repo-level instructions so GitHub Copilot follows the LOCKED naming rules
(lowercase concatenated DB columns, allowed-acronym list, banned shorthand),
the ASCII-only style policy, and the plugin/migration/contract architecture.
Without this Copilot suggests snake_case columns, em-dashes, and
db.create_all(), which the naming hook and CI then reject. Distilled from
CONTRIBUTING.md; that file stays the authority.
