The node-engine owns the composition it alone runs (H1, H2)

ADR 0593 §1 and §7: compose, its bus reader and runtime reader, takein,
validate, the overlay generator, the composer's run and mesh-compose, and
the judgement of a move leave mesh-sdk for the node-engine's internal
packages, so no other module composes and a change to them rebuilds only
the node-engine. The shapes others read (the composer's request and
verdict, the overlay's names, compositions and answers) stay in mesh-sdk.
The node's grant is now a golden file of what the grants part composes,
since the composer of the bus's user list leaves mesh-sdk too.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

cmd/mesh-compose/testdata/mesh-catalog/modules/messenger/module.json.captured

@@ -0,0 +1,196 @@
+{
+  "module": "messenger",
+  "version": "1",
+  "slug": "msgr",
+  "runs-as": "messenger",
+  "seats": [
+    {
+      "name": "operator-channel",
+      "scope": "mesh",
+      "serves": [
+        "open",
+        "history",
+        "notify",
+        "tell",
+        "asks"
+      ],
+      "accepts": [
+        "ask",
+        "cancel",
+        "condition"
+      ],
+      "emits": [
+        "decided"
+      ],
+      "by-caller": [
+        "ask",
+        "cancel",
+        "condition",
+        "decided"
+      ],
+      "records": [
+        "asks"
+      ]
+    },
+    {
+      "name": "channel",
+      "scope": "mesh",
+      "kinded": true,
+      "accepts": [
+        "show",
+        "edit",
+        "send"
+      ]
+    },
+    {
+      "name": "intake",
+      "scope": "mesh",
+      "kinded": true,
+      "emits": [
+        "choice",
+        "link",
+        "failed",
+        "standing"
+      ],
+      "proofs": [
+        "code"
+      ]
+    }
+  ],
+  "claims": [
+    {
+      "name": "operator-channel",
+      "scope": "mesh",
+      "serves": [
+        "open",
+        "history",
+        "notify",
+        "tell",
+        "asks"
+      ]
+    }
+  ],
+  "uses": [
+    "channel"
+  ],
+  "consumes": [
+    "mesh-controller.condition-raised",
+    "mesh-controller.condition-changed",
+    "mesh-controller.condition-cleared",
+    "mesh-controller.plan-moved",
+    "intake.choice",
+    "intake.link",
+    "intake.failed",
+    "intake.standing"
+  ],
+  "emits": [
+    "refused"
+  ],
+  "invokes": [
+    "seat:mesh-controller.conditions",
+    "seat:mesh-controller.root-free",
+    "seat:issue-tracker.tracking"
+  ],
+  "state": [
+    "open",
+    "sent",
+    {
+      "name": "asks",
+      "ttl-seconds": 2592000
+    },
+    "identities",
+    "walks"
+  ],
+  "own-secrets": {
+    "broker": "${dir:state}/broker"
+  },
+  "secrets-owner": "messenger",
+  "tools": [
+    "messenger_status",
+    "messenger_recent",
+    "messenger_test",
+    "messenger_preview",
+    "messenger_check",
+    "messenger_identities",
+    "messenger_unlink"
+  ],
+  "config": {
+    "time-zone": {
+      "type": "string",
+      "description": "The time zone every time a message says is said in, an IANA name such as Europe/Brussels; empty is this machine's own zone.",
+      "trusted": true,
+      "default": ""
+    },
+    "desktop-machines": {
+      "type": "list",
+      "description": "The machines whose desktop showed the operator's messages, by node name. Nothing in this module reads it since the desk channel took the desktop over; it is taken so the file stays as a layer that still sets it makes it, until that layer drops it.",
+      "trusted": true,
+      "default": []
+    },
+    "only-what-needs-me": {
+      "type": "list",
+      "description": "The kinds of channel set to say only what needs the operator: a walk that delivered with nothing held and nothing open is not told there (ADR 0308 §4); empty is none.",
+      "trusted": true,
+      "default": []
+    },
+    "messages-per-hour": {
+      "type": "number",
+      "description": "messages per channel per hour before the rest are held as one; 0 turns the pause off. The tell verb has its own cap of 10 and is not counted here.",
+      "minimum": 0,
+      "maximum": 1000,
+      "trusted": false,
+      "default": 100
+    }
+  },
+  "resources": [
+    {
+      "id": "account",
+      "type": "user",
+      "name": "messenger",
+      "shell": "/usr/bin/nologin",
+      "home": "/var/lib/messenger"
+    },
+    {
+      "id": "state",
+      "type": "directory",
+      "mode": "0700",
+      "place": ".",
+      "owner": "messenger",
+      "unknown": "program"
+    },
+    {
+      "id": "settings",
+      "type": "file",
+      "path": "${dir:state}/settings.json",
+      "mode": "0600",
+      "takes-config": ["time-zone", "desktop-machines", "only-what-needs-me", "messages-per-hour"],
+      "merge": "json",
+      "template": "files/settings.json",
+      "owner": "messenger"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/messenger",
+        "binary": "messenger",
+        "loads": [
+          "messenger"
+        ],
+        "env": {
+          "MESH_MESSENGER_SETTINGS": "${dir:state}/settings.json",
+          "MESH_MESSENGER_STATE": "${dir:state}"
+        }
+      },
+      {
+        "name": "files",
+        "kind": "archive",
+        "from": "files"
+      }
+    ]
+  }
+}