Check that every generated registrar is wired into its service

calendar_name_registrar.cpp and day_counter_registrar.cpp, and their history providers, were generated but never called from registrar.cpp; a request to their subjects answered with no responder until this was fixed by hand. Add a check, in the codegen drift gate or a unit test, that every generated handler and history provider registrar is called by its service's registrar.

A new entity can ship with no server answering it, and nothing fails until a screen asks.

• projects/ores.refdata/core/src/messaging/registrar.cpp
• compass-codegen-fix-drift skill — the registrar wiring check it describes

• Capture