Publish Browser Route Run

Browser-safe route run metadata for history and resume.

is_owner / can_refine default True because every serializer except the shared read (#1549) is owner-scoped; the non-owner projection clears them and nulls the owner-only fields below (session linkage, provenance, composer prompt, published pages), which is why those three are str | None even though the owner path always populates them.

Browser-safe public route-page data for a route option.