Add AbCipEmulateNestedUdtTests (skip-gated, AB_SERVER_PROFILE=emulate) to close
the live-gate gap for nested-struct UDT discovery via CIP Template Object (class 0x6C)
threaded by commits 3d8ce4e8/d203f31c. Compiles + skips cleanly against ab_server
(no CIP Template Object service). Update docs/drivers/AbCip.md nested-struct section
to record the shipped decode path, the Emulate-only live-gate, and offline unit coverage.
Joseph Doherty