A declaration carries its order, and a host refuses an older one

novox/hq 04-ISSUES/107. A declaration's only identity was the digest of
its bytes: a host could say "not the last" and could not say "older". On
the link, nothing refused an older one at all, and the drain picked the
last to arrive — wrong exactly when it mattered, a backlog drained out of
order or a broker that split a burst.

A declaration may now carry a sequence, one higher per send. A host
refuses one lower than what it kept, whole, and says why. The drain keeps
the highest sequence in a batch rather than the last to arrive.

Only when both sides claim an order. Absent reads as zero — "no ordering
claimed", not "first" — so a controller that sends none is still
understood and a host that kept one before it understood them compares
nothing. That is what lets hosts go first and the controller follow, which
is the order 087 says a new field needs.

internal/declaration/declaration.go

@@ -1137,6 +1137,19 @@ type Declaration struct {
 	// converged node — which is every node the mesh raised before adoption existed, and so the
 	// only form an older controller ever sends (novox/hq ADR 0100).
 	Adoption *Adoption
+
+	// Sequence orders this declaration against every other the mesh has sent this node: each
+	// send is one higher than the last, assigned under the control plane's hold on the node
+	// (novox/hq 04-ISSUES/107). Zero is a declaration that carries no order — every one an older
+	// controller sent, and the bundle genesis applies — and a host makes no ordering claim about
+	// one of those.
+	//
+	// **The one property a declaration needs that its signature does not give it.** A signature
+	// says the mesh sent this; it cannot say the mesh sent it AFTER the one the host is holding.
+	// Before this, "older" was inferred from arrival within a batch and a 750ms window, and a
+	// backlog longer than the batch, or a slow broker, applied a declaration the mesh had already
+	// superseded.
+	Sequence int64
 }
 
 // Adoption is a node's mode, as the controller records it: the node is adopted, and these are
@@ -1274,6 +1287,9 @@ type envelope struct {
 	// a bug quietly strip a machine.
 	OwnsNothing bool              `json:"owns_nothing,omitempty"`
 	Resources   []json.RawMessage `json:"resources"`
+	// Sequence is optional on the wire, so a controller that does not send one is still
+	// understood: absent reads as zero, which is "no ordering claimed" rather than "first".
+	Sequence int64 `json:"sequence,omitempty"`
 }
 
 func parse(raw []byte, allowActions bool) (*Declaration, error) {
@@ -1290,7 +1306,7 @@ func parse(raw []byte, allowActions bool) (*Declaration, error) {
 			env.Version, Version)}}
 	}
 
-	d := &Declaration{Version: env.Version, For: env.For, Adoption: env.Adoption}
+	d := &Declaration{Version: env.Version, For: env.For, Adoption: env.Adoption, Sequence: env.Sequence}
 	var problems []string
 
 	if len(env.Resources) == 0 && !env.OwnsNothing {