A definition names no host path for its own data

Twenty-eight modules' data directories are placed: the root as place ".", a sub-directory named by
its id, and every host-side reference — binds, secrets, own secrets, grants, receives, file paths,
mounts, env-files — as ${dir:<id>}. Resolved on the default root every path is the one the manifest
named before, which the controller's TestPlacedDirectoriesKeepTheirPaths proves over both checkouts;
so no data moves and no machine sees a change. Five directories whose id is not their last segment
keep their path as a placement (novox/hq issue 119, ADR 0112, design 27).

modules/mesh-vault/module.json

@@ -21,10 +21,10 @@
     "mesh-vault.secret.deprovisioned"
   ],
   "receives": {
-    "secret": "/var/lib/mesh-vault/grants/mesh.json"
+    "secret": "${dir:grants}/mesh.json"
   },
   "grants": {
-    "secret": "/var/lib/mesh-vault/grants"
+    "secret": "${dir:grants}"
   },
   "keeps": "/var/lib/mesh-vault/root",
   "own-secrets": {
@@ -40,25 +40,22 @@
     {
       "id": "state",
       "type": "directory",
-      "path": "/var/lib/mesh-vault",
-      "mode": "0700"
+      "mode": "0700",
+      "place": "."
     },
     {
       "id": "grants",
       "type": "directory",
-      "path": "/var/lib/mesh-vault/grants",
       "mode": "0700"
     },
     {
       "id": "ledger",
       "type": "directory",
-      "path": "/var/lib/mesh-vault/ledger",
       "mode": "0700"
     },
     {
       "id": "root",
       "type": "directory",
-      "path": "/var/lib/mesh-vault/root",
       "mode": "0700"
     },
     {
@@ -68,15 +65,15 @@
       "network": "host",
       "volumes": [
         "/var/lib/mesh/mesh-vault/broker:/run/secrets/broker:ro",
-        "/var/lib/mesh-vault/grants:/var/lib/mesh-vault/grants:ro",
-        "/var/lib/mesh-vault/ledger:/var/lib/mesh-vault/ledger",
-        "/var/lib/mesh-vault/root:/var/lib/mesh-vault/root:ro"
+        "${dir:grants}:${dir:grants}:ro",
+        "${dir:ledger}:${dir:ledger}",
+        "${dir:root}:${dir:root}:ro"
       ],
       "env": {
         "MESH_BROKER_FILE": "/run/secrets/broker",
-        "MESH_RECEIVES": "/var/lib/mesh-vault/grants/mesh.json",
-        "MESH_VAULT_LEDGER": "/var/lib/mesh-vault/ledger",
-        "MESH_VAULT_ROOT": "/var/lib/mesh-vault/root"
+        "MESH_RECEIVES": "${dir:grants}/mesh.json",
+        "MESH_VAULT_LEDGER": "${dir:ledger}",
+        "MESH_VAULT_ROOT": "${dir:root}"
       },
       "artifact": "runtime"
     }