Added Chinese language support and smooth mouse wheel scrolling.

[nellwhoami]

Added Chinese language support and smooth mouse wheel scrolling.

[TomBadash]

Thanks for this great contribution @nellwhoami! We've merged the following into master with your attribution:

Merged:

• Multi-language UI system (English, Simplified Chinese, Traditional Chinese)
• Language picker in Settings
• All QML/tray/accessibility dialog translations
• Page Up, Page Down, Home, End navigation actions
• Chinese README (as README_CN.md - we kept English as the primary README.md)

Still open for review:

• Scroll speed multiplier (wasn't working on Windows during testing)
• Smooth scrolling (macOS-only, needs testing by a macOS contributor)
• macOS button dispatch optimization (inline vs queue)
• macOS build script changes

Could you rebase this PR on the latest master so it only contains the remaining changes? That way we can review and test them separately.

Also - would you be interested in writing a short guide on how to add new languages? It would help other contributors translate Mouser into more languages and spread the word!

One small tip for next time: if each feature has its own commit (or even its own PR), it makes the review process much faster and smoother. For example, i18n in one commit, new actions in another, scroll speed in another. That way we can approve and merge features independently without having to cherry-pick. Just something to keep in mind for future contributions!

Thanks again for the work on this. If you get a chance to test the merged changes on your end, let us know how it works for you - feedback always helps!