Agent instructions

The standards for working in this repository are in STANDARDS.md. This file is the portable pointer to them, because AGENTS.md is the format many coding agents read; CLAUDE.md points here too. STANDARDS.md is the single source, so this file stays a pointer rather than a copy that could drift from it.

In a project that adopts this baseline, AGENTS.md is instead a full copy of STANDARDS.md, because that project has no STANDARDS.md of its own. See USING.md and D-015 in DECISIONS.md.