A module that listens is served, not run

`run` imports an entrypoint without binding a broker — it exists for a step that
works offline and exits. Both the catalogue and amqp-ping subscribe on import,
so both died on the first on() with no broker bound.

modules/amqp-ping/module.json

@@ -51,10 +51,6 @@
       "env-file": [
         "/var/lib/amqp-ping/amqp.env"
       ],
-      "args": [
-        "run",
-        "/app/modules/amqp-ping/dist/index.js"
-      ],
       "restart-on": [
         "amqp-env"
       ],

modules/mesh-catalog/Dockerfile

@@ -36,7 +36,10 @@ COPY --from=build /app/modules/mesh-catalog/dist /app/modules/mesh-catalog/dist
 # base image's own node_modules — the module gets its extra dependency without shadowing the sdk it
 # was compiled against.
 COPY --from=build /deps/node_modules /app/modules/mesh-catalog/node_modules
-# What a tool host should load: the catalogue's tools. Its consumer of `module.builder.built` is the
-# other entrypoint, and is what this module's own container runs — named in the declaration's `args`
-# rather than here, because which one runs is the declaration's business.
-ENV MESH_TOOL_MODULES=/app/modules/mesh-catalog/dist/tools/index.js
+# Both entrypoints, loaded in serve mode.
+#
+# **A consumer cannot be started with `run`.** That mode imports an entrypoint without binding a
+# broker — it is for a step that does its work offline and exits — and the catalogue's whole job is
+# to listen for what the builder announces. Serve binds the broker first, then imports these, so
+# `on()` has something to subscribe to.
+ENV MESH_TOOL_MODULES=/app/modules/mesh-catalog/dist/index.js,/app/modules/mesh-catalog/dist/tools/index.js

modules/mesh-catalog/module.json

@@ -72,10 +72,6 @@
         "/var/lib/mesh-catalog/db.env"
       ],
       "artifact": "runtime",
-      "args": [
-        "run",
-        "/app/modules/mesh-catalog/dist/index.js"
-      ],
       "restart-on": [
         "db-env"
       ]