Check the tool runtime's own code before it merges, every test on a bus of its own (hq ADR 0237)

A merge-check.sh, the repository's layer of the mesh's merge check (mesh/repo-check):
format, vet, and node-tools' suite under the race detector. The tests shared one bus and
had to run one package at a time; like the controller's (#97), each now starts a server
of its own at the release go.mod pins, held to the catalogue's bus image by a test. What
cannot run in the check — bundles that need @novox/mesh-sdk — is said as not tested.

merge-check.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+# mesh-check-toolchain: go
+#
+# The tool runtime's own check (novox/hq ADR 0237 as amended): the second layer of a pull request's merge
+# check, `mesh/repo-check`, run by the build seat in the mesh's Go toolchain — and by hand.
+#
+# The gate — every machine of the facts snapshot composed with this change — is the build seat's first
+# layer (`mesh/merge-gate`), run because the mesh's module graph builds node-tools and mesh-tools from
+# here. This is the code's own: node-tools (Go) formatted, vetted and its suite, every test on a bus of its
+# own at the release the mesh runs (internal/meshtest), packages in parallel, under the race detector when
+# the toolchain has a C compiler.
+#
+# **Said, never passed silently**: the runtime's and the console's tests launch TypeScript and Python
+# bundles that import the mesh's own package (@novox/mesh-sdk), which comes from the package registry — and
+# a check of code nobody has approved is given no credential for it. Where node and that package are not
+# present those two packages are not tested here, and the TypeScript in node-tools/src neither.
+set -eu
+cd node-tools
+
+unformatted=$(gofmt -l cmd internal)
+if [ -n "$unformatted" ]; then
+	echo "not gofmt'd:"
+	echo "$unformatted"
+	exit 1
+fi
+CGO_ENABLED=0 go vet ./...
+
+packages=$(go list ./...)
+if ! command -v node >/dev/null 2>&1 || [ ! -d node_modules/@novox/mesh-sdk ]; then
+	echo "NOT TESTED HERE: internal/runtime and internal/console launch bundles that need node and @novox/mesh-sdk"
+	packages=$(printf '%s\n' "$packages" | grep -v -e '/internal/runtime$' -e '/internal/console$')
+fi
+if command -v gcc >/dev/null 2>&1; then
+	CGO_ENABLED=1 go test -race -count=1 $packages
+else
+	echo "NOT RACE-CHECKED: the toolchain holds no C compiler; the suite runs without the race detector"
+	CGO_ENABLED=0 go test -count=1 $packages
+fi
+echo "NOT TESTED HERE: node-tools/src (TypeScript) needs @novox/mesh-sdk from the package registry"