node-tools in Go: the node's runtime, launch-only, wire-compatible with the TypeScript (hq ADR 0193)

The runtime knows no language, so nothing ties it to Node.js. This ports its serve mode — the
pinned bus connection and patient connect, following memberships, launching every served bundle
over MCP on stdio with its own environment, a child's emit published as its module, each tool,
the tools verb and seat verbs served where the mesh issued them, and the console on loopback —
to one static binary. Same subjects, request and reply bodies, event headers and MCP answers.
The TypeScript stays: it is still the runtime inside the per-module containers until WP4c.
Tests run against a real bus and share the TypeScript fixtures.

node-tools/internal/meshtest/sprintf.go

@@ -0,0 +1,5 @@
+package meshtest
+
+import "fmt"
+
+func sprintf(format string, args ...any) string { return fmt.Sprintf(format, args...) }