v2.6.0: Show highest-altitude flight of the day on Statistics screen

Adds FlightLogbook::todayMaxAltitude(), which scans today's logbook
CSV for the entry with the greatest altitude at first sighting, and
displays it as "Highest flight today: <callsign> (<alt> ft)" on the
Statistics screen (Menu -> Flight Options -> Statistics).

Also documents the CYD-flightradar.bin rename step (for GitHub
release uploads) in the CLAUDE.md release workflow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/i18n_it.h

@@ -117,6 +117,7 @@ static const char* const I18N_IT[] = {
     "Tocca di nuovo per confermare!",
     "Registro reimpostato.",
     "Tempo di attività: ",
+    "Volo più alto oggi: ",
     "Cronologia (ultimi 7 giorni)",
     "Ancora nessun dato.",
     "Come funziona la cronologia",