fix: install local iso failed

[redscholar]

What type of PR is this?

/kind bug

What this PR does / why we need it:

This PR fixes two bugs in the offline repository installation logic that prevent KubeKey from using local ISO repositories on Debian/Ubuntu nodes.

1. Fixes incorrect local ISO path check:
   In install_package.yaml, the condition [ -f "{{ .tmp_dir }}/iso" ] checks a mount directory using the -f (file) test, which always returns false. This causes the script to skip the local repository branch and fall back to public APT mirrors (archive.ubuntu.com), which are unreachable in offline/air-gapped environments. The condition is changed to [ -f "{{ .tmp_dir }}/repository.iso" ] to correctly detect the ISO file.

2. Fixes mismatched backup/restore filenames:
   The backup step uses the suffix kubekey-$now.bak (timestamp before .bak), but the restore step incorrectly uses kubekey.bak-$now (timestamp after .bak). Because the filenames do not match, the original APT/YUM source configurations fail to restore after package installation.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Please verify that:
- In `builtin/core/roles/native/repository/tasks/install_package.yaml`, both the Debian and RHEL branches now use `repository.iso` for the local source detection.
- In `builtin/capkk/roles/init/init-os/tasks/init_repository.yaml`, the backup and restore filenames are now consistent for both APT and YUM flows.

Does this PR introduced a user-facing change?

Fixed a bug where offline nodes incorrectly attempted to connect to public Ubuntu repositories instead of using the local ISO repository, causing package installation to fail in air-gapped environments.

Additional documentation, usage docs, etc.:

[kubesphere-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: redscholar

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• OWNERS [redscholar]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[gemini-code-assist]

Code Review

This pull request updates the backup file naming convention for repository files, renames the ISO file check to repository.iso, and refines the processing of OS version IDs in templates. Feedback was provided regarding the use of unquoted variables containing spaces in shell commands, which could lead to execution failures. Additionally, it was suggested to convert version IDs to lowercase for better consistency and compatibility with file naming conventions.

[gemini-code-assist]

For consistency with the Kylin implementation (line 26) and to ensure compatibility with lowercase filenames commonly used for ISO images, the VERSION_ID should be converted to lowercase. This also removes an unnecessary double space after the lower filter.

          {{ .os.release.ID | replace "\"" "" | unquote | trim | lower }}{{ .os.release.VERSION_ID | replace "\"" "" | unquote | trim | lower }}

[gemini-code-assist]

The VERSION_ID should be converted to lowercase for consistency and to avoid potential mismatches with lowercase filenames.

          {{ .os.release.ID | replace "\"" "" | unquote | trim | lower }}-{{ .os.release.VERSION_ID | replace "\"" "" | unquote | trim | lower }}