The contract tests no longer compiled on main (AtnItem::dictionary is now
Vec<u8>, so it is compared with b"Future event"), sat outside main's
tests/it layout, and the new atn.yml added six legs (two macOS) to every
PR against ci.yml's policy. Move the tests into tests/it so the existing
CI runs them, drop atn.yml and docs/atn-testing.md, keep main's ci.yml and
fuzz target, and note the committed fixtures in ATTRIBUTION.md.
Co-authored-by: denstu473 <63150090+denstu473@users.noreply.github.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>