Fleet-heal RF Status lambda: dead first snprintf truncates 4 hex chars into a 4-byte buffer (GCC -Wformat-truncation on every hub build)

Seen 2026-09-14 in both hub OTA builds: dsc-hub-fleet-heal.yaml:381 snprintf(assoc3, sizeof(assoc3) /4/, “%02X%02X”, b[4], b[5]) wants 5 bytes. snprintf bounds it (no overflow), and line 383 immediately overwrites assoc3 with the intended 3-char “%02X%X” form, so the first call is dead code whose only effect is the warning. Fix: delete line 381. Fold into the next hub firmware change; not worth a flash on its own.