Share one fixed eight-column tab-stop contract across core and GPU renderers. Consolidate byte-to-display-column accounting, expand GPU code tabs with source provenance, align caret/hit/decoration geometry, and refresh minimap projection on edits.
Make protocol-version constraints merge-order independent, require wrapped-tab decoration coverage, and explicitly exclude hover panel sizing.
Define the fixed cross-frontend tab-stop contract, GPU source projection and mapping rules, core display-width consolidation, minimap behavior, and acceptance gates.
Levi Neuwirth