[ProfessorShroom]

Add flight destination to aircraft tags

ADS-B doesn't include where a flight is going, so this looks up each aircraft's callsign on adsbdb.com (free, no API key) and adds a green line to its tag, e.g. to Amsterdam.

How it works

• Lookups run on the existing ADS-B fetch task, one HTTPS connection at a time.
• Only aircraft inside the outer ring (the ones that get a tag) are looked up, nearest first, at most 2 per cycle.
• Results are cached (48 callsigns): found 2 h, not found 30 min, errors 30 s. Rate limiting backs off for 60 s.
• Planes with no route data show no extra line.
• City names are shown when they fit (up to 15 characters), otherwise the airport code. Names are converted to plain ASCII (Zürich → Zurich) because the tag font only has ASCII.
• The serial log prints the full route and free heap, e.g. route: TRA91T Thessaloniki to Amsterdam (SKG>AMS) [heap free ..., lowest ...].

Settings

• Setup portal: new "Show flight destination" checkbox (on by default). Turning it off stops all lookups.
• config.h: kRouteLookupsPerCycle, kRouteUseCityNames, kRouteMaxCityChars, kRouteShowOrigin (adds a from <city> line).

Notes

• Aircraft callsigns are sent to adsbdb.com. This is documented in the README.
• New files: route_client (lookup and cache) and ascii_fold (accent folding). Aircraft gains a has_flight_callsign flag.

[ProfessorShroom]

Do these just get ignored?