A build's outcome belongs to the role, not to the module holding it

ADR 0121. The builder declared `built` as its own event, so every consumer depended
on which module happens to be the build machine today. It is the build-machine
role's event now: the builder declares none of its own, and the catalogue listens
for `mesh-build-machine.built` rather than `builder.built`.

Nothing changes about what reaches the catalogue. What changes is that it survives
the build machine being a different module, which is the whole reason the mesh has a
word for a role.

modules/builder/module.json

@@ -20,9 +20,6 @@
   "secrets": {
     "npm-package-registry": "/var/lib/mesh/builder/package-registry.secret"
   },
-  "emits": [
-    "built"
-  ],
   "own-secrets": {
     "broker": "/var/lib/mesh/builder/broker"
   },

modules/mesh-catalog/index.ts

@@ -1,6 +1,6 @@
 // mesh-catalog's entrypoint — the module graph's consumer (novox/hq ADR 0070, ADR 0072).
 //
-// The builder announces what it built; this places it in the graph and announces what that means.
+// The build-machine role announces what it built; this places it in the graph and announces what that means.
 // The control plane hooks the *meaning* — a module was upgraded — rather than the build output, so
 // it never has to interpret an artifact or ask this module anything.
 //
@@ -47,7 +47,7 @@ interface Built {
   replay?: boolean;
 }
 
-await on("builder.built", async (event) => {
+await on("mesh-build-machine.built", async (event) => {
   const body = event.body as Built;
   if (!body.module || !body.commit) {
     // Said rather than dropped: a build that announced itself without saying what it built is a

modules/mesh-catalog/module.json

@@ -29,7 +29,7 @@
     "broker": "/var/lib/mesh/mesh-catalog/broker"
   },
   "consumes": [
-    "builder.built"
+    "mesh-build-machine.built"
   ],
   "emits": [
     "registered",