Keep the packages this node's compositions declare in the engine's own key, and answer them on the node seat (ADR 0565 clauses 6 and 15, issue 1953)

pacman still reads the controller's mirror because no engine wrote its key: the engine
now keeps each handed composition's package resources and, after a pass that handed
something new, writes mesh-host_packages.<node> only when the value differs, owed after
the growing bound when refused. The manifest declares the state so the grants part
creates it. The verb packages answers the key beside the mirror's key for the node and
their difference, and with write writes the key again from what was composed. H8's
integration test proves the write under the grant the grants part composes.

Needs mesh-sdk feat/node-packages (0ef7c0c) for DeclaredPackagesOf and the engine's read of the
mirror (go.mod pin left for the lead: the SDK commit is not pushed).

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

cmd/mesh-host/nodeagent.go

@@ -1024,6 +1024,9 @@ func selfComposer(ctx context.Context, session *link.Session, node string, say f
 	// And it keeps each placed module's data items in its own state data, which the node's disk-load watches (novox/hq
 	// ADR 0577 clause 1); the shadow composes for candidates and keeps none.
 	env.Data = link.EngineData{Session: session}
+	// And the packages its compositions declare in its own key of the state packages, which pacman reads (novox/hq ADR
+	// 0565 §6).
+	env.Packages = link.EnginePackages{Session: session}
 	unreadable := ""
 	placed, err := selfcompose.Placed(ctx, env.Get, node, link.Backoff, func(m string) {
 		if strings.Contains(m, "cannot be read") {