Take the catalogue's composition rules into the node-engine

ADR 0593 §7: the composer with its refusals leaves mesh-sdk, so mesh-sdk
carries no composition rule. The catalogue functions only the
node-engine's composition reaches (Resolve, Resolution's Compose,
Declaration, DataItems, LeftOut, Rules and the rest, the settings,
placeholder and template refusals, the rendering helpers) are copied
with their tests into internal/compose/resolution; a method of a
mesh-sdk shape becomes a function taking it first. The composition
calls its own copies, and the captured catalogue its tests read lives
here now, shared by mesh-compose's tests.

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

internal/compose/resolution/template.go

@@ -0,0 +1,31 @@
+package resolution
+
+import (
+	"fmt"
+	"strings"
+
+	mcat "git.novox.be/novox/mesh-sdk/go/catalogue"
+)
+
+// HeldTemplateProblem is why a manifest cannot be held by the mesh because it still names a template, or "": the
+// manifest the mesh holds carries every file's text, which a build reads back from its templates archive. One
+// naming a template was resolved by a builder that does not read templates, and would compose files with no text.
+func HeldTemplateProblem(m mcat.Manifest) string {
+	var named []string
+	for _, r := range m.Resources {
+		if t, has := r[mcat.TemplateField]; has {
+			named = append(named, fmt.Sprintf("%v (%v)", r["id"], t))
+		}
+	}
+	for _, it := range m.Items {
+		if it.Template != "" {
+			named = append(named, fmt.Sprintf("its item of %s (%s)", it.Collection, it.Template))
+		}
+	}
+	if len(named) == 0 {
+		return ""
+	}
+	return fmt.Sprintf("%s still names the template(s) of %s: the manifest the mesh holds carries each file's "+
+		"text, read back from the build's templates archive — this one was resolved by a builder that does not "+
+		"read templates, or not built at all (novox/hq ADR 0349 §2)", m.Module, strings.Join(named, ", "))
+}