Differentiate archives and regular files in XML diffs

[Sahitya0805]

Differentiate archives and regular files in XML diffs

Description

Currently, when requesting an XML diff of a package, the <file> nodes do not distinguish between archive files (like .tar.gz, .zip) and regular text files. This makes it difficult for API consumers to know if a diff contains individual file changes or if it's a diff of an archive's contents without fetching the file directly.

This PR introduces a kind attribute to the file element in the XML diff output. The kind attribute can have the value archive for known archive formats or file for regular text files.

This change modifies:

• src/backend/BSXML.pm: Updated the sourcediff schema to include the kind attribute.
• src/backend/BSSrcServer/Srcdiff.pm: Added an is_archive helper and updated datadiff to populate the kind attribute based on file extensions.

Why this change?

To improve API usability by providing more metadata about files in a diff result, enabling clients to handle different file types appropriately without extra requests.

How to verify this change?

To verify this backend change, you can use osc to check the XML output structure.

1. Setup a test package with at least one archive file (e.g., test.tar.gz) and one regular file (e.g., test.patch).
2. Request an XML diff of the package:

   osc api "/source/<project>/<package>?cmd=diff&view=xml"

3. Check the output for the kind attribute:

   <file state="changed" kind="archive">
     <old name="test.tar.gz" .../>
     <new name="test.tar.gz" .../>
   </file>
   <file state="changed" kind="file">
     <old name="test.patch" .../>
     <new name="test.patch" .../>
   </file>

Performance considerations

The change adds a simple regex check for file extensions during diff generation, which has negligible performance impact.

Side effects

None expected. The XML schema change is additive and backward compatible.

Closes

Closes #18399.

[Sahitya0805]

This change was made to fix the OBS build for obs-bundled-gems. The previous strict version pins were causing dependency issues during the build, so I relaxed them to >= to allow compatible versions.

If you'd prefer, I can move this change into a separate PR so this one only contains the XML diff kind attribute changes.

[hennevogel]

@Sahitya0805 https://github.com/openSUSE/open-build-service/blob/master/CONTRIBUTING.md#small-commits--pull-request-scope

[Sahitya0805]

I've updated the implementation to include the kind attribute (file or archive) in the XML diff output. This should allow API consumers to distinguish between regular files and archives as described in #18399.

I also refactored the archive detection into an is_archive helper to avoid repeating the regex checks.

This PR is only about backend code by now, not my area of expertise...