Fetch a catalog JSON by URL (the runtime-fetch model — packs ship as data files in dist, not
inlined into the code bundle, so command strings stay out of the JS and user-supplied packs can be
pointed at their own URL). Typically wrapped in a lazy loader:
register(domain, tag, () => fetchCatalog(new URL('./sheet.cmd.json', import.meta.url))).
Fetch a catalog JSON by URL (the runtime-fetch model — packs ship as data files in
dist, not inlined into the code bundle, so command strings stay out of the JS and user-supplied packs can be pointed at their own URL). Typically wrapped in a lazy loader:register(domain, tag, () => fetchCatalog(new URL('./sheet.cmd.json', import.meta.url))).