Normalize size units and intrinsic sizing across Elisp and native layout. Add help, pointer, hover-style and keymap support with reusable interaction adapters.
Keep content updates local, preserve scroll caches and hover borders, and avoid rebuilding retained plans and ownership metadata for stable geometry.
Validation: make check and native-rust-tests passed; targeted native interaction and scroll publication regressions passed.
Split the verified renderer, layout engine, Grid support, native boundary, tests, examples, and paired documentation into the independent Ebox repository. Keep ETAF and application concerns outside this package.
