Request: Multilingual support for app.merginmaps.com interface, Transifex integration

I'd like to suggest adding multilingual support to the app.merginmaps.com interface, similar to what already exists for the Mergin Maps mobile app.

Currently, the web interface is available only in English, which can be a barrier for many users. Localized versions would greatly enhance usability for non-English-speaking users.

Why this would be useful:

• Improves accessibility and inclusivity-
• Supports broader adoption in non-English-speaking regions-
• Aligns with the localization already done in the mobile app-
• Eases onboarding for users in public sector, education, and field work

Suggested approach:

• Add support for language files in the web frontend.
• Integrate the project with Transifex
• The mobile app already uses Transifex, so the same workflow could likely be reused

Beginne damit zu untersuchen, wie das Web-Frontend derzeit mit Benutzeroberflächentexten umgeht und wie die mobile Mergin Maps-App Transifex verwendet. Die Aufgabe ist abgeschlossen, wenn die Weboberfläche Sprachdateien und einen Transifex-Workflow unterstützt, wobei das Issue keine bestimmten Dateien oder Tests nennt.