Backup resources (plans, backupjobs, backups) are not
ApplicationDefinitions, so ensureNavigation() never adds their
baseFactoriesMapping entries. Without these mappings the OpenUI
frontend cannot resolve the {cluster} context for backup pages,
producing broken sidebar links with an empty cluster segment
(e.g. /openapi-ui//tenant-root/...).

Add the three missing entries to the static Navigation resource.

Assisted-By: Claude AI
Signed-off-by: Kirill Ilin <stitch14@yandex.ru>
(cherry picked from commit 398ca58)