Change `repositories_by_id` to return `impl Iterator<Item = Result<RepositoryInfo,
RepositoryError>>`
instead of `Result<Vec<RepositoryInfo>, RepositoryError>`.
This allows callers to handle failures on a per-repository basis rather
than having the
entire operation fail if a single repository lookup fails.
Previously, the method would stop processing and return an error as soon
as any repository failed to load. Now it processes all repositories and
returns individual results, making the API more resilient and giving
callers
more control over error handling.
6d0c571ea9