[salmun-nister]

Fixes #10

Change

Panel.qml - require a positive sample instead of mere presence. A live idle draw is tens of watts, so this cannot hide a dish that does measure:

   readonly property bool hasPower: {
     var p = h ? h.powerW : []
-    for (var i = 0; i < p.length; i++) if (p[i] !== null && p[i] !== undefined) return true
+    for (var i = 0; i < p.length; i++) if (p[i] > 0) return true
     return false
   }

Both existing consumers follow the flag, so no layout surgery: visible: root.hasPower on the section, and the adjacent chart's width (parent.width when hidden, half when shown).

Model.js - keep the bar tooltip consistent:

-  if (live.powerW !== null && live.powerW !== undefined) parts.push(fmtW(live.powerW))
+  // 0 means the dish does not meter draw (see Panel.qml hasPower): leave it
+  // out of the tooltip rather than reporting a false 0.0 W.
+  if (live.powerW > 0) parts.push(fmtW(live.powerW))

README.md - one line under Requirements, where dish-capability notes belong:

- A dish that reports power draw (optional; the power block is hidden when
  every sample is 0 W, since such hardware does not meter draw)

Testing

case	expected
all-zero ring (affected hardware)	block hidden, neighbouring chart full width, tooltip has no power segment
metered ring (one sample at 15.3 W)	block shown, tooltip unchanged
empty ring / hist.json not yet read	unchanged (hidden)
powerW absent from status.json	no exception, no power segment

Scope

Display only; backend/bin/starlinkd untouched. Independent of the other open PRs.