node-engine.composition shows the node's own fields and what the last pass held (issue 774)

Reading ace's node composition gave four resources twice and no way to see that one revision named no provisioner
client's account. The verb now shows, for module node, the revision's provisioner account beside what runs names, its
adoption, how many identities, groups and libraries it names, and each module the composer's last pass held with why.

Claude-Session: https://claude.ai/code/session_01JG73KG7AfSdh6FP8VrBqCn

internal/agent/agent.go

@@ -136,6 +136,9 @@ type Env struct {
 	// Revisions are a composition key's revisions the bucket keeps, oldest first; nil reads none. The composition a want
 	// names is taken from them when a newer one replaced it under the same key (ADR 0539 clause 1).
 	Revisions func(ctx context.Context, key string) ([]Update, error)
+	// Held is what the node's composer held in its last pass, each module with why, as the verb composition shows it
+	// for the node's own (issue 774); nil says nothing.
+	Held func() map[string]string
 	// Settled is told a module's apply or removal that succeeded, once what runs holds it (Everything), outside the
 	// agent's lock: the declaration the node applies now names what that composition names, its filled files among
 	// them. The node-engine's filling tells the provisioner's client then to fill again what it refused (mesh-host