v0.7.0

fix(codex): bump README Status block to 0.7.0 for the publish gate

publish.yml's doc-consistency gate requires the ## Status block to
already reference the new version before the tag is pushed (checked via
grep against packages/codex/README.md, alongside the version-history
entry and CHANGELOG's first heading). I'd left Status at 0.6.1 reasoning
it was "still accurate pre-publish" -- wrong call, this repo's own
convention (enforced by the gate, not just style) is to bump it in the
same commit as the version. First v0.7.0 publish run
(run 30617786799) failed here, before ever reaching npm -- confirmed
nothing published (npm view still shows 0.5.0..0.6.1 only). Verified all
3 doc gate regexes pass locally before pushing this.

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com