API
- Content: New achievement, "Boneless Boss", for collecting invertebrate pets (@CuriousMagpie)
- Fix: Raise party member limit to 30 from 29 (@SabreCat)
- Fix: Check party member limit when inviting using @-username (@SabreCat)
- Fix: If i18n string token in user's preferred language is translated to an empty string, fall back to English (@SabreCat)
- Performance: Remove needless query parameter in auth middleware (@SabreCat)