Radiosonde route now runs a quick import check before launching the full
subprocess, catching missing Python dependencies immediately with a clear
message instead of a truncated traceback. Error messages are context-aware:
import errors suggest re-running setup.sh rather than checking SDR connections.
Increased stderr truncation limit from 200 to 500 chars and added full stderr
logging via logger.error() across all affected routes (radiosonde, ais, aprs,
acars, vdl2) for easier debugging.
Closes#173
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>