A supplementary file attached to a Lesson. Resource is a first-class domain
entity in v1 (not a field of Lesson) so the Workbook view, analytics, and
shared Resources are possible without a refactor — see design.md §D1.
url accepts either an absolute URL or a site-relative path beginning
with / (v1's static-asset convention — see design.md §D9 "Resource URL:
static or signed").
A supplementary file attached to a Lesson. Resource is a first-class domain entity in v1 (not a field of Lesson) so the Workbook view, analytics, and shared Resources are possible without a refactor — see design.md §D1.
urlaccepts either an absolute URL or a site-relative path beginning with/(v1's static-asset convention — see design.md §D9 "Resource URL: static or signed").