turbo.json's boundary config already allows `feature -> feature`, and
the cross-feature event system depends on it — a consumer must import
the publisher's event contract from `@repo/<publisher>`. But the ESLint
boundaries config, ADR-010, and AGENTS.md still declared
`feature -> [core, tooling]`, contradicting turbo.json and the shipped
code (marketing-pages imports @repo/auth).
Align all three to turbo.json: a feature may import another feature's
published public exports. Internals stay sealed by the `exports` map,
and cross-feature behaviour still flows through IEventBus.