Add Russian and Ukrainian localizations

[TinyFrontier]

Summary

• add complete Russian and Ukrainian UI translations
• localize permission prompts, Finder service labels, dynamic content, and user-facing errors
• register Russian and Ukrainian in the language picker and Xcode resources
• add localization parity, format-specifier, duplicate-key, and bundle-packaging tests
• update the supported-language list in the README

Why

PureMac did not previously support Russian or Ukrainian, and several dynamically constructed strings bypassed the localization lookup even when translation keys existed.

User impact

Russian- and Ukrainian-speaking users can select their language in Settings and use the complete GUI, including onboarding, Full Disk Access guidance, cleanup flows, permission prompts, and Finder services. The selected language still applies after relaunch, matching the existing language-switching behavior.

Validation

• generated the project with XcodeGen 2.46.0
• built the universal Release configuration for arm64 and x86_64
• ran the complete XCTest suite: 10 tests, 0 failures
• verified all .strings, plist, entitlement, and project files with plutil
• verified localization key parity, format specifiers, duplicate keys, and packaged bundle resources
• manually smoke-tested Russian and Ukrainian in the app

[boombertz]

Hi @TinyFrontier

Following the CONTRIBUTING.md and for a better follow up of your changes, could you split the commit beyond the localizations?

There are more than Russian and Ukrainian and translations in your PR.

[TinyFrontier]

@boombertz Thanks for the feedback. I rebased the branch onto the latest main, removed the unrelated copy/error behavior changes, and split the work into three focused commits: dynamic UI localization, Russian and Ukrainian resources, and localization tests. The Universal Release build and all 10 tests pass.