Function merge_dict_into_mutable_metadata_lossy 

pub fn merge_dict_into_mutable_metadata_lossy(
    base: &mut GroupMutableMetadata,
    extensions: &Extensions<GroupContext>,
) -> Vec<GroupMutableMetadataError>

Best-effort variant of merge_dict_into_mutable_metadata that degrades per-field instead of failing per-group: every component that decodes is applied to base, every component that doesn’t is skipped, and the errors are returned so the caller can log them (empty vec = clean merge).

Exists for the archive exporter, where one malformed component must not drop the whole group from a backup — the group’s messages are exported unconditionally, so a missing group row orphans them and aborts the entire restore on a foreign-key violation. Non-export callers that want fail-fast semantics keep using the strict variant above.