feedback7: AGENTS.md and CLAUDE.md — an entry point for AI coding assistants (GitHub #379 by @anAtheist987; the owner's OK of 2026-10-08)

- AGENTS.md only indexes the existing documents (ARCHITECTURE, DESIGN index, SIM / META / DATA / I18N, the kits README)
  and their hard rules (official first + [ASSUMED], sim determinism and detmath, golden results, generated data, no game
  art, t() strings, docs with the code, commit / PR conventions, verification commands); CONTRIBUTING.md stays the full
  text. CLAUDE.md is one line pointing to it.
- Tests: docs-paths, docs-consistency.

CLAUDE.md

@@ -0,0 +1,3 @@
+# CLAUDE.md
+
+Read [AGENTS.md](AGENTS.md) — the entry point for AI coding assistants (what to read first, the hard rules, how to verify).