Read a done build once, and work out the data items in the scope the pass composed in (ADR 0577)

The data items after a pass re-read each placed module's build over the bus (about 55 per pass on
ace, g14 and shanks); a done build never changes, so the composer keeps it. The items are now
worked out with the pass's own kept builds and modules run inside the node's own, as composed.

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

internal/selfcompose/data.go

@@ -50,7 +50,13 @@ func (c *Composer) publishData(ctx context.Context) {
 	if !due || c.env.Data == nil {
 		return
 	}
-	items, unplaced, err := dataItemsOf(ctx, itemsReader{reader{c: c}}, c.env.Mesh, frombus.Scope{Node: c.env.Node})
+	c.mu.Lock()
+	scope := c.dataScope
+	c.mu.Unlock()
+	if scope.Node == "" {
+		scope.Node = c.env.Node
+	}
+	items, unplaced, err := dataItemsOf(ctx, itemsReader{reader{c: c}}, c.env.Mesh, scope)
 	if err != nil {
 		c.sayData("the data items of this node's modules cannot be worked out, and what the engine's state " +
 			delivery.EngineDataBucket + " holds stands: " + err.Error())