SD-M2d sdk: a seat family on the shared events stream keeps no longer than the stream

Holds operator-channel's decided to the shared stream's 7 days (the lead's ruling of 12:5x), and each registry seat's
family with it.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

go/buscompose/names_test.go

@@ -4,7 +4,12 @@ import (
 	"strings"
 	"testing"
 
+	"git.novox.be/novox/mesh-contracts/go/seats/containerimageregistry"
+	"git.novox.be/novox/mesh-contracts/go/seats/gopackageregistry"
 	"git.novox.be/novox/mesh-contracts/go/seats/meshbroker"
+	"git.novox.be/novox/mesh-contracts/go/seats/npmpackageregistry"
+	"git.novox.be/novox/mesh-contracts/go/seats/ociartifactregistry"
+	"git.novox.be/novox/mesh-contracts/go/seats/operatorchannel"
 	"git.novox.be/novox/mesh-sdk/go/membership"
 )
 
@@ -43,6 +48,17 @@ func TestTheBusNamesAgree(t *testing.T) {
 			}
 		}
 	}
+	// A seat family on the shared events stream is kept as long as the stream keeps it: its contract says no more.
+	for family, days := range map[string]int{operatorchannel.Family: operatorchannel.FamilyMaxAgeDays,
+		npmpackageregistry.Family: npmpackageregistry.FamilyMaxAgeDays, gopackageregistry.Family: gopackageregistry.FamilyMaxAgeDays,
+		containerimageregistry.Family: containerimageregistry.FamilyMaxAgeDays,
+		ociartifactregistry.Family:    ociartifactregistry.FamilyMaxAgeDays} {
+		for _, st := range MeshStreams() {
+			if st.Name == EventsStream && int64(days)*24*60*60 != int64(st.MaxAge) {
+				t.Errorf("the family %s says %d days, the shared events stream keeps %d s", family, days, st.MaxAge)
+			}
+		}
+	}
 }
 
 // subjectTakes says whether a subject pattern (`*` one token, `>` the rest) takes a subject.