# Description

Consolidating spec-derived resolution reduces repeated traversal and keeps the runtime’s cache behavior predictable. Narrowing the root entrypoint to the plugin-facing API makes the stable surface explicit while leaving internal helpers free to change.

# Changes

- Cached source, artifact, section, and ready-source lookups behind a shared spec-derived map
- Updated runtime path, state, and search helpers to use the cached lookups and preserve source state more consistently
- Reduced the root export surface to the plugin-facing API and refreshed docs, tests, and release metadata

BREAKING CHANGE: the root entrypoint no longer re-exports low-level helpers; consumers should import only the plugin-facing API from the package root.