catalogue: a module's own object bucket, its reader grant and a stream that keeps its history, so the knowledge base can keep its records on the bus (ADR 0592 §5, §6, §9)

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

go/catalogue/streams.go

@@ -35,6 +35,12 @@ const GrantKey = "{key}"
 // is the mesh's own limits retention — kept until it ages or the stream fills, dropping its oldest.
 const StreamRetentionWorkQueue = "work-queue"
 
+// StreamRetentionHistory is a stream's declared retention that keeps its history (novox/hq ADR 0592 §6): every message
+// is kept with no maximum age, and when the stream reaches its maximum size the bus refuses a new message rather than
+// dropping its oldest. It takes no max-age-days, max-deliveries or duplicates; the mesh raises a condition when it
+// passes FullWarnPercent of its cap.
+const StreamRetentionHistory = "history"
+
 // StreamLeastDeliveries and StreamMostDeliveries bound a work-queue stream's max-deliveries (novox/hq ADR
 // 0436 §6): how many times a message is handed over before it is given up as a dead letter.
 const (
@@ -57,7 +63,8 @@ type StreamDeclaration struct {
 	// Grant restricts it, when said.
 	Grant *StreamGrant `json:"grant,omitempty"`
 	// Retention is how the stream decides what to keep when it fills (novox/hq ADR 0436 §6): empty for the
-	// mesh's own limits retention (dropping its oldest), or StreamRetentionWorkQueue.
+	// mesh's own limits retention (dropping its oldest), StreamRetentionWorkQueue, or StreamRetentionHistory
+	// (novox/hq ADR 0592 §6).
 	Retention string `json:"retention,omitempty"`
 	// MaxDeliveries bounds how many times a work-queue message is handed over, 1 to 10; refused without
 	// retention work-queue (novox/hq ADR 0436 §6).
@@ -104,14 +111,21 @@ func (g *StreamGrant) UnmarshalJSON(raw []byte) error {
 	return nil
 }
 
-// Days is the stream's age in days, the default where none is said.
+// Days is the stream's age in days, the default where none is said, and 0 (no maximum age) for a stream that keeps its
+// history.
 func (s StreamDeclaration) Days() int {
+	if s.KeepsHistory() {
+		return 0
+	}
 	if s.MaxAgeDays == 0 {
 		return StreamDefaultDays
 	}
 	return s.MaxAgeDays
 }
 
+// KeepsHistory says the stream keeps every message and refuses a new one when full (StreamRetentionHistory).
+func (s StreamDeclaration) KeepsHistory() bool { return s.Retention == StreamRetentionHistory }
+
 // Cap is the stream's size in MiB, the default where none is said.
 func (s StreamDeclaration) Cap() int {
 	if s.MaxMiB == 0 {