feat(i18n): add Brazilian Portuguese localization

[maylton]

Summary

Adds the initial internationalization infrastructure and Brazilian Portuguese
localization for Sleex.

Changes

• Add Qt Linguist integration with an embedded translation catalog
• Load translations automatically from the system locale
• Add Brazilian Portuguese (pt_BR) translations
• Localize the settings application and its individual pages
• Add local Ollama-assisted tools for translating TS catalogs and marking QML strings
• Preserve placeholders and exclude Material Symbol icon names from translation
• Ignore generated Python cache files

Testing

• Built the project successfully with CMake
• Confirmed that the pt_BR catalog is installed at runtime
• Tested translation lookup with qsTranslate()
• Tested the settings application using the local QML entrypoint
• Verified translated settings pages, sidebar labels, tooltips, Wi-Fi messages,
  privacy options, interface options, sound settings and behavior settings
• Confirmed there are no unfinished translations
• Confirmed the Git working tree is clean

Refs #105

[LeVraiArdox]

Hello, thanks for the PR !

Although the translation is a very good improvement for Sleex, I don't think this is the right way to do it.

Firstly, we can't just use AI for this type of task. An 8B LLM is unpredictable and we can't let it rewrite the source code. Also, it's not a clean way to generate translations.

Then, instead of using QTranslator, it would probably be better to write a custom service that search for a string to translate (wrapped in a function, for example Translations.tr("stuff")), and translate it with a translation dictionary. The dictionary can be hand written or AI written if reviewed afterward, but it's on the translator's end. By translator I mean the person that translates.

If you want to take the challenge, go ahead. Else, you can close this PR. Thanks anyway :)

[maylton]

Hi there!

I totally agree with you. Using AI to translate everything isn't the best way neither the safest. It was more of an example of possibility than a real implementation 😅

I liked your idea and I'll try to do it. I'm not so good and coding, that's why I vibe code most of it (you clearly noticed it 🤣). If that's okay, I'll be glad to help.

[LeVraiArdox]

I have no problem with vibe coding, as long as it respects the code style and have a human review behind. Also, AI sometimes makes useless comments, that can be avoided.

Tho, I recommend you to try to understand the code that is generated, AI can be a good learning tool ;)