Keep each placed module's data items in the engine's state data, so disk-load measures without composing (ADR 0577)

After a pass that handed a new composition, the node's composer works out its modules' data
items from the inputs it composed from and writes each module's key <node>.<module> of
mesh-host_data only when it differs, deleting the keys of modules that left. Pins mesh-sdk
feat/data-items for the contract and the engine's grant. Two tool-answer tests are merged so
the unit count stays where it was.

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

packaging/operator_keys_test.go

@@ -77,7 +77,10 @@ func TestTheManifestConsumesTheBackupEvent(t *testing.T) {
 	}
 	// 774 (the alert table): the state health, one key per node, the node's own health report, kept until
 	// written again (no TTL: a node that stops writing keeps its last word, which the watchman reads with its time).
-	if len(parsed.State) != 1 || parsed.State[0].Name != "health" || parsed.State[0].TTLSeconds != 0 {
+	// ADR 0577 clause 1: and the state data, one key per module placed on the node that declares data items, kept until
+	// the module leaves the node; created by the grants part from this manifest as health is.
+	if len(parsed.State) != 2 || parsed.State[0].Name != "health" || parsed.State[0].TTLSeconds != 0 ||
+		parsed.State[1].Name != "data" || parsed.State[1].TTLSeconds != 0 {
 		t.Fatalf("the manifest declares the state %+v", parsed.State)
 	}
 }