Feature: Added support for changing encoding when extracting ZIP files

[oxygen-dioxide]

ZIP file specifications historically use the system's local encoding (e.g., CP936 for Chinese, Shift_JIS for Japanese) to store filenames, rather than UTF-8. This causes cross-language compatibility issues: for example, filenames created by Japanese users (Shift_JIS) will appear as garbled text when extracted by Chinese users (using GBK/CP936), and vice versa. English-speaking users rarely encounter this issue since most legacy encodings are Latin-compatible, but it remains critical for multilingual users.

This PR adds an encoding selection option during ZIP extraction. Users can manually override the default system encoding (e.g., to Shift_JIS, UTF-8, GBK, Big5, etc.) to ensure filenames are decoded correctly. (defaults to system encoding to reserve backward compatibility)

Resolved / Related Issues

To prevent extra work, all changes to the Files codebase must link to an approved issue marked as Ready to build. Please insert the issue number following the hashtag with the issue number that this Pull Request resolves.

• Bug: File names for Japanese zips aren't shown correctly on Chinese language #14937 is partially solved in this PR. (See the "TODO" part below)

Steps used to test these changes

Stability is a top priority for Files and all changes are required to go through testing before being merged into the repo. Please include a list of steps that you used to test this PR.

I'm a Chinese user, so I don't know whether and how the encoding issue affects English users. Below is how I test this on Simplified Chinese windows.

1. Download this zip file:
   japanese-example.zip
2. In Files, right click this file, Extract -> Extract Files
3. Select "Japanese (Shift-JIS)" encoding
   

The file names in this zip file are Japanese encoded in Shift-JIS. Here are the results of extraction:
Extracted with Shift-JIS (correct)

Extracted with default encoding (previous behaviour which is incorrect):

TODO

• Autometically guess encoding
• Being able to select encoding when viewing a zip file

[yaira2]

LGTM