i18n(tray): translate About strings + drop all fuzzy entries

Translate the 3 new About msgids in fr/de/es/it/uk/pt. Also clear every
preexisting fuzzy entry across all locales: msgmerge had left ~42-53 stale
fuzzy guesses per language (e.g. "Save folder:" -> "Échec de l'enregistrement"),
already excluded from the .mo by msgfmt. Drop the fuzzy flag and reset those
to untranslated, so no .po carries a fuzzy and everything compiles to a clean
English fallback. Recompile all .mo.

Author: rcspam