fix(firms): label a snapshot that ends at a set time with that time, not LIVE

A FIRMS source may answer the 24 hours to a set time, naming its end as
`at` (epoch ms). The layer row then reads "24 h to MM-DD HH:MM UTC"
instead of "LIVE · updated ...", and getStats() reports `at`. A
snapshot without `at` (the trailing 24 hours to now, as the dev proxy
serves) keeps the LIVE label. Translated in every catalog.

src/i18n/locales/it.json

@@ -734,6 +734,7 @@
   "loading...": "caricamento...",
   "KEY REQUIRED": "CHIAVE RICHIESTA",
   "LIVE · updated {age}": "LIVE · aggiornato {age}",
+  "24 h to {day} {time} UTC": "24 h fino al {day} {time} UTC",
   "Source snapshot time unavailable": "Ora dello snapshot della fonte non disponibile",
   "Live data unavailable": "Dati live non disponibili",
   "Intel Picture": "Quadro intelligence",