The wasm-plugin ABI contract now lives in the cms (block/cms/abi/v1 + docs) and
the ninja CLI moved to its own repo (block/cli). Core keeps abi/ as the guest
SDK until WO-WZ-027. Removes cmd/ninja, the dead orchestrator registry client
(internal/api/orchestrator), the moved docs, and the now-unused ninja/orchclient
deps from go.mod/go.sum.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
