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/icecast.json

@@ -0,0 +1,47 @@
+{
+  "module": "icecast",
+  "version": "1",
+  "capabilities": [
+    "container-runtime"
+  ],
+  "own-secrets": {
+    "source": "/var/lib/icecast-module/source.secret",
+    "admin": "/var/lib/icecast-module/admin.secret",
+    "relay": "/var/lib/icecast-module/relay.secret"
+  },
+  "listens": [
+    {
+      "port": 8000,
+      "protocol": "tcp",
+      "from": "mesh",
+      "why": "streams in from sources and out to listeners"
+    }
+  ],
+  "resources": [
+    {
+      "id": "state",
+      "type": "directory",
+      "path": "/var/lib/icecast-module",
+      "mode": "0700"
+    },
+    {
+      "id": "server-env",
+      "type": "file",
+      "path": "/var/lib/icecast-module/server.env",
+      "mode": "0600",
+      "content": "ICECAST_SOURCE_PASSWORD=${secret:source}\nICECAST_ADMIN_PASSWORD=${secret:admin}\nICECAST_RELAY_PASSWORD=${secret:relay}\nICECAST_ADMIN_USERNAME=admin\n"
+    },
+    {
+      "id": "server",
+      "type": "container",
+      "name": "icecast",
+      "image": "infiniteproject/icecast@sha256:cd506cf3dfe31ce05fd37d7e672dbd1213e7255cc93d28ecf5a3b547af4e162c",
+      "env-file": [
+        "/var/lib/icecast-module/server.env"
+      ],
+      "ports": [
+        "8000"
+      ]
+    }
+  ]
+}