The node-engine owns the composition it alone runs (H1, H2)

ADR 0593 §1 and §7: compose, its bus reader and runtime reader, takein,
validate, the overlay generator, the composer's run and mesh-compose, and
the judgement of a move leave mesh-sdk for the node-engine's internal
packages, so no other module composes and a change to them rebuilds only
the node-engine. The shapes others read (the composer's request and
verdict, the overlay's names, compositions and answers) stay in mesh-sdk.
The node's grant is now a golden file of what the grants part composes,
since the composer of the bus's user list leaves mesh-sdk too.

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

internal/validate/validate.go

@@ -0,0 +1,42 @@
+// Package validate is the node-engine's own judgement of a declaration, for whoever must know before
+// a declaration is sent whether a machine would take it (novox/hq to-be 45 §4, D1; §9, the merge gate).
+//
+// **One validator.** The controller composed declarations the host then refused whole — a manifest
+// the catalogue check passed (novox/hq issue 236), a consumer's identity too long for the machine's
+// names (issue 263) — because the only validator was the one the host runs as it applies. A second,
+// written in the controller from the host's rules, would drift from them the first time either
+// changed. So the host's own parsing is exported here, unchanged: what the controller's self-check and
+// the merge gate run is what every machine runs.
+//
+// Copied from mesh-host at commit 619e14aa8e572c5056e3d2a2412c7f8b364bf840 (validate/validate.go), unchanged but for
+// the import path of the parser, which is mesh-sdk's go/declaration (novox/hq ADR 0453 clause 3, ADR 0446 clause 4).
+// mesh-host keeps its own copy until release 4b.
+//
+// It judges a declaration as it arrives over the link: actions are refused, as the host refuses them
+// from the link (novox/hq ADR 0005). Nothing here touches a machine.
+package validate
+
+import (
+	"errors"
+
+	"git.novox.be/novox/mesh-sdk/go/declaration"
+)
+
+// Declaration is every problem the node-engine would refuse a declaration for, each in its own words;
+// nil when it would take it. The body is the declaration as the controller composes it — the bytes a
+// signature is made over — not the signed envelope.
+func Declaration(raw []byte) []string {
+	_, err := declaration.Parse(raw)
+	if err == nil {
+		return nil
+	}
+	var refused *declaration.RefusalError
+	if errors.As(err, &refused) {
+		return refused.Problems
+	}
+	return []string{err.Error()}
+}
+
+// Version is the declaration vocabulary this validator speaks: a declaration of another version is
+// refused whole by Declaration, as by the host.
+const Version = declaration.Version