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/engine_seat.go

@@ -0,0 +1,11 @@
+package resolution
+
+import (
+	mcat "git.novox.be/novox/mesh-sdk/go/catalogue"
+)
+
+// engineSeat is the seat's row in the closed set.
+func engineSeat() mcat.Seat {
+	return mcat.Seat{Name: mcat.EngineSeat, Scope: mcat.ScopeNode, Serves: mcat.EngineVerbs(), Emits: append([]string(nil), mcat.EngineEvents...),
+		HeldByTheEngine: true, Decision: "novox/hq ADR 0563"}
+}