node-tools launches every bundle it serves; a child's emit is published as its module (hq ADR 0193)

Every served entrypoint is started as a process speaking MCP over stdio, told its module and node;
one that is not executable is refused by name. The import path, the SDK resolve hook (issue 209)
and the per-registration hand-off go. The one-module form the per-module containers use is still
imported until they move (to-be 38 WP4c). A child's mesh/publish is published as its module and
answered once accepted; a child that dies says why in its own last words. Fixtures are served
through launchers exactly as the builder writes them.

node-tools/test/node-tools-serve.test.ts

@@ -36,7 +36,7 @@ test("as node-tools, serve loads the bundles and is the console on loopback", as
     env: {
       ...process.env,
       MESH_BROKER_FILE: credential,
-      MESH_TOOL_MODULES: `alpha=${fixture("many-alpha.mjs")}`,
+      MESH_TOOL_MODULES: `alpha=${fixture("many-alpha.serve.mjs")}`,
       MESH_CONSOLE_LISTEN: "127.0.0.1:0",
     },
     stdio: ["ignore", "pipe", "pipe"],