The controller marks a deliberately-empty declaration owns_nothing (hq 127)

The host refuses an empty body unless told the emptiness is meant
(mesh-host#29). When a node's declaration composes to no resources —
which #77 now sends rather than skips — Body() sets owns_nothing, so
the node applies it and drops what it last held. A declaration with
resources never carries the marker. One test.

cmd/mesh-controller/sendable.go

@@ -38,6 +38,12 @@ func (s sendable) Body() ([]byte, error) {
 	if s.Adoption != nil {
 		envelope["adoption"] = s.Adoption
 	}
+	// An empty declaration is deliberate here — the node owns nothing the mesh put there
+	// (novox/hq issue 127) — and the host refuses an empty body unless it is told the emptiness
+	// is meant, so a truncated or mis-composed body is never mistaken for "own nothing".
+	if len(s.Resources) == 0 {
+		envelope["owns_nothing"] = true
+	}
 	return json.Marshal(envelope)
 }