feat: support [folder] template string in localIdentName option

[mochiya98]

Summary

Support [folder] template string in localIdentName option

close #11184

Related links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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Pull Request Overview

This PR adds support for [folder] template strings in the localIdentName option for CSS modules. This allows users to include the parent directory name in their CSS class name generation.

• Added [folder] template string support to localIdentName option
• Extracted folder name from the resource file path using Path::new().parent().file_name()
• Integrated folder replacement logic into the existing template string system

[CPunisher]

Could you please add some tests?

[mochiya98]

Sorry about that - since this was my first contribution, I wasn’t sure where the related tests were located, so I hadn’t added.
I’ve identified the appropriate spot and added them. Could you check if this looks okay? ( _ _)m

• If the file is in a subdirectory, it uses the name of the nearest directory
• If the file is directly under the root, it becomes an empty string

[codspeed-hq]

CodSpeed Performance Report

Merging #11356 will not alter performance

_{Comparing mochiya98:folder-local-ident-name (74962e0) with main (19b2442)}

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Summary

✅ 17 untouched benchmarks

[CPunisher]

Thanks!