Documents the MediaAsset model, future GET/POST/DELETE/PATCH /media contract,
and the MediaRepository interface (Mock IndexedDB-backed now, Http later via
DI swap) that Sprint 4 will implement against. Media assets never enter the
Bootstrap model, consistent with ADR-0001.
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.
