Fix envelope version and add a TODO comment

core.go

@@ -15,7 +15,7 @@ func (s *Session) Close(data []byte) (*Letter, error) { //nolint:gocognit
 	letter := &Letter{}
 
 	if s.wire == nil || s.wire.msgNo == 0 {
-		letter.Version = 1
+		letter.Version = s.envelope.Version
 		letter.SuiteID = s.envelope.SuiteID
 	}
 

envelope.go

@@ -188,6 +188,7 @@ func (e *Envelope) prepSignets(signets []*Signet, recipients bool, storage Trust
 			// keys are _always_ signets
 			if signet.Scheme == SignetSchemeKey {
 				recipients = false
+				// TODO: spills to next loop
 			}
 
 			// signet is referrer