postgres builds its own runtime, like any other module

Its provisioner container named an image nobody could produce — a zero digest
placeholder. It names an artifact instead, and the module says how to build it,
so the mesh can make the database provider the catalogue needs.

modules/postgres/Dockerfile

@@ -0,0 +1,28 @@
+# postgres's runtime: the tool runtime, carrying this module's compiled provisioner, tools and
+# event consumer.
+#
+# **Built from this module's own directory and nothing else.** The sdk is in the base image, so
+# nothing is copied out of a neighbouring checkout — which is what lets the mesh build this from a
+# repository and a path (novox/hq ADR 0069) rather than only on a workstation that happens to have
+# the siblings.
+#
+# The base is named by ARG so it can be pinned to a digest the mesh's registry assigned. A tag would
+# make this runtime's contents depend on what somebody last pushed under that name.
+ARG RUNTIME_BASE=127.0.0.1:5000/mesh-tool-runtime@sha256:d4d793c828a5f563fdd8f49e5c6026d17b308a3f7a13c589849188362e4c7415
+
+FROM ${RUNTIME_BASE} AS build
+# Compiled under /app/modules so `@novox/mesh-sdk` resolves upward into the base's own
+# node_modules — the module is compiled against exactly the sdk it will run against.
+WORKDIR /app/modules/postgres
+COPY . .
+# The compiler is invoked by its real path rather than through node_modules/.bin, whose entries are
+# symlinks to a launcher that requires its library relatively — resolved away when the base image
+# was assembled.
+RUN node /app/node_modules/typescript/bin/tsc client.ts index.ts provisioner/index.ts tools/index.ts \
+      --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist
+
+FROM ${RUNTIME_BASE}
+COPY --from=build /app/modules/postgres/dist /app/modules/postgres/dist
+# Which of the three the container runs is the declaration's business, said in its `args` — one
+# image, because they are one module and share a client.
+ENV MESH_TOOL_MODULES=/app/modules/postgres/dist/index.js

modules/postgres/module.json

@@ -102,7 +102,6 @@
       "id": "runtime",
       "type": "container",
       "name": "mesh-postgres",
-      "image": "mesh-runtime-postgres@sha256:0000000000000000000000000000000000000000000000000000000000000000",
       "network": "postgres",
       "volumes": [
         "/var/lib/mesh/postgres/broker:/run/secrets/broker:ro",
@@ -114,7 +113,21 @@
         "MESH_PROVISION_PASSWORD_FILE": "/run/secrets/superuser",
         "MESH_BROKER_FILE": "/run/secrets/broker",
         "MESH_RECEIVES": "/var/lib/postgres/grants/mesh.json"
-      }
+      },
+      "artifact": "runtime",
+      "args": [
+        "run",
+        "/app/modules/postgres/dist/provisioner/index.js"
+      ]
     }
-  ]
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "runtime",
+        "kind": "image",
+        "from": "Dockerfile"
+      }
+    ]
+  }
 }