The feature JSON payload switched to `id`, `isEnabled`, and `appstream`,
and made `documentation` an array of URLs.
`updatectl` still parsed legacy table-derived names and a single URL.
This broke feature JSON parsing and made output inconsistent.
Features without documentation could also cause a null dereference.
Align `updatectl` with the current schema and preserve all
documentation URLs across sysupdate, D-Bus, and Varlink payloads.
Propagate condition evaluation errors through `condition_test_list()`
and `feature_is_suggested()`, with consistent JSON error handling and
tests.
The `suggested` field is now optional and always a boolean when
present; it is omitted rather than set to an error string when
SuggestOn*= conditions cannot be evaluated.
Add `suggested` metadata and document the field transition.
Follow-up for 3e34ccf6df.
Follow-up for 75a247d4de.
Follow-up for 40e727c93b.
Fixes#43603
dongshengyuan
Lennart Poettering