Three more: nodered, icecast, portainer

Node-RED and Icecast are the plain shapes — a data directory owned by
the number inside, generated passwords in a host-written env file, one
declared port each.

Portainer mounts the container runtime's socket, which is the mount
04-ISSUES/026 is reopened about: a machine facility, not the module's
data, spelled today exactly like a data directory. It is converted as
it runs now rather than held hostage to that vocabulary — the same
mount the builder already carries — and it will be the second citation
when 026 gets its answer.

Letta stays unconverted for now: the arrangement being replaced pins a
year-old image of a fast-moving project, and converting a pin nobody
would keep is not fidelity. It wants a fresh look at what version to
run, which is a decision and not a translation.

All pinned by real digests, resolved on this workstation today.

examples/modules/portainer.json

@@ -0,0 +1,36 @@
+{
+  "module": "portainer",
+  "version": "1",
+  "capabilities": [
+    "container-runtime"
+  ],
+  "listens": [
+    {
+      "port": 9443,
+      "protocol": "tcp",
+      "from": "mesh",
+      "why": "the container dashboard, over its own tls"
+    }
+  ],
+  "resources": [
+    {
+      "id": "data",
+      "type": "directory",
+      "path": "/services/portainer/data",
+      "mode": "0700"
+    },
+    {
+      "id": "server",
+      "type": "container",
+      "name": "portainer",
+      "image": "portainer/portainer-ce@sha256:511f3f06c96fe3b993ebeaafde311c1959cae73a7ef825dba6397d51b450dffa",
+      "ports": [
+        "9443"
+      ],
+      "volumes": [
+        "/services/portainer/data:/data",
+        "/var/run/docker.sock:/var/run/docker.sock"
+      ]
+    }
+  ]
+}