The result of listScopePackages.
packages is empty only when source is none, and reason is present
exactly when something went wrong — on stale-cache it says why the
refresh failed, on none it says why there is no list at all.
readonly
packages: readonly ScopePackage[]
The scope's published packages, sorted by name, without @binstruct/cli.
Every entry names something jsr:@binstruct/<name> resolves to; reserved
names with no version behind them are not members.
readonly
source: ListingSource
Where they came from.
readonly
optional
reason: string
Why the network answer is missing, when it is.