11-task plan extending the existing /builder editor: route-driven
tabs, generic Languages/Navigation tabs, a dependency-free rich HTML
editor, client-side draft/publish + validation, and a dirty-state
guard. Notes the repo has no test runner configured, so tasks use
manual verification instead of automated specs.
Records the multi-tenant marketplace platform architecture as ADR-0001
(bootstrap-driven, config-only frontend) with a source-backed fact pack,
and writes the approved Sprint 16 design for extending the existing
project editor with Languages/Navigation tabs, an HTML editor, and a
client-side draft/publish flow.
