i18n: Add Swedish translation and improve internationalization support

[yeager]

Summary

authd has user-facing strings that are currently hardcoded in English, including authentication mode labels and error messages. The existing po/ directory in authd-oidc-brokers has an empty fr.po, suggesting i18n is planned but not yet implemented.

Current state

• authd-oidc-brokers/internal/broker/authmodes/consts.go has display labels:
  • "Local Password Authentication"
  • "Device Authentication"
  • "Define your local password"
• Error messages in broker.go ("Error connecting to provider", etc.)
• authd-oidc-brokers/po/fr.po exists but is 0 bytes
• No .pot template file

Proposal

I'd like to contribute a Swedish (sv) translation once the i18n infrastructure is in place. Questions:

1. Is there a plan for extracting translatable strings (e.g. using go-i18n or gotext)?
2. Should translations go through Launchpad, or directly as .po files in the repo?
3. Are the PAM/GDM-facing strings also planned for translation?

Happy to help set up the gettext extraction if useful.

Daniel Nylander — Swedish translator for GNOME, Ubuntu, Debian, and 70+ open source projects.

[adombeck]

Thanks for filing the issue and for the offer to help! It might indeed be time to tackle i18n in authd. We'll discuss in the team how to prioritize this and come back to you.