fix: support ckanext-files resources

[aleks-iv]

Proposed fixes:

• Support archive previews for resources managed by ckanext-files with url_type=file.
• Read archives through temporary storage URLs when available, with a streaming fallback for other storage backends.
• Preserve existing behavior for standard CKAN uploads and remote URLs.
• Add regression coverage and bump the patch version to 2.3.4.

[mutantsan]

Thanks, @aleks-iv, I have a few comments:

1. I don't like the way get_archive_tree looks right now. The _prepare_file_resource function is now used for file and upload resources. I'd make a check as I did for cloud storage above and run the necessary code to prepare the url only when the url_type is file.
2. The test looks really complicated, hard to say what you're testing
3. This is not a bug, as the files didn't exist when the extension was written. It's a feature that implements support for file resources. Therefore, the version must be 2.4.0

[aleks-iv]

@mutantsan, thanks, for the review.
Updated:

1. File preparation now runs only for url_type=file.
2. Simplified the test.
3. Bumped the version to 2.4.0.