Add language selection to posthog analytics

[SylvainChevalier]

The footer has a drop down menu to select your preferred language, including untranslated. Let's record what each user has set in Posthog analytics.

[SylvainChevalier]

@claude

[claude]

Claude finished @SylvainChevalier's task in 1m 27s —— View job • claude/issue-4125-20260121-1335 • Create PR ➔

---

Todo List

• Read repository setup instructions (CLAUDE.md)
• Find footer language selection component
• Locate PostHog analytics integration
• Implement language tracking in PostHog
  • Add language property to user identification
  • Track language change events in footer
  • Track language change events in settings page
• Commit and push changes
• Provide PR creation link

Changes Made

I've successfully added language selection tracking to PostHog analytics. The implementation includes:

1. front_end/src/contexts/auth_context.tsx:32-39 - Added language property to PostHog user identification, so every user's language preference is tracked as a user property

2. front_end/src/app/(main)/components/footer.tsx:167-184 - Added PostHog tracking when language is changed via the footer dropdown:

   • Captures a language_changed event with previous and new language
   • Updates the user's language property in PostHog

3. front_end/src/app/(main)/accounts/settings/(general)/components/language_preferences.tsx:24-43 - Added PostHog tracking when language is changed in the settings page with the same tracking behavior

What's being tracked

• User Property: language - The user's current language preference (set on login and updated on change)
• Event: language_changed - Fired whenever a user changes their language, includes:
  • previous_language: The language they were using before
  • new_language: The language they selected

This allows you to analyze language preferences and track when users switch languages in PostHog.

Pull Request

--- |