Carry the power draw to the bar over the bus, not through a file (hq ADR 0260)

Modules talk over the bus. The power module's bundle puts each fresh reading of its own
sampler in its state draw, keyed by the machine; the bar's block shows that state, which
the bar's bundle watches under the read the mesh grants it. A new catalogue check refuses
a module naming another module's path under /run or /var/lib.

modules/power/module.json

@@ -20,6 +20,12 @@
     "on-battery",
     "battery-low"
   ],
+  "state": [
+    {
+      "name": "draw",
+      "ttl-seconds": 30
+    }
+  ],
   "tools": [
     "power_state",
     "power_hooks",
@@ -235,6 +241,12 @@
       "state": "running",
       "boot": "enabled"
     },
+    {
+      "id": "draw-dir",
+      "type": "directory",
+      "path": "/run/mesh-power",
+      "mode": "0755"
+    },
     {
       "id": "draw",
       "type": "process",
@@ -289,10 +301,9 @@
         "bar": "bottom",
         "place": "status",
         "order": 45,
-        "shows": "command",
+        "shows": "state",
         "options": {
-          "command": "/usr/local/lib/mesh-power/bin/power-draw",
-          "interval": 5
+          "state": "power.draw"
         }
       }
     }