smcli env: emit URI/USERNAME/PASSWORD for consumers; pin v5

convert of login items keeps original env names in fields; env now also
exposes the login triple so sourced consumers can map to legacy names.
Ticket: https://projects.knownelement.com/issues/832

cli/cmd/smcli/main.go

@@ -251,6 +251,15 @@ func cmdEnv(name string) error {
 		v := strings.ReplaceAll(f.Value, "'", "'\\''")
 		fmt.Printf("export %s='%s'\n", f.Name, v)
 	}
+	if len(pc.URIs) > 0 {
+		fmt.Printf("export URI='%s'\n", pc.URIs[0])
+	}
+	if pc.Login.Username != "" {
+		fmt.Printf("export USERNAME='%s'\n", pc.Login.Username)
+	}
+	if pc.Login.Password != "" {
+		fmt.Printf("export PASSWORD='%s'\n", pc.Login.Password)
+	}
 	return nil
 }
 
@@ -537,3 +546,5 @@ func cmdConvert(name string) error {
 	fmt.Printf("converted: %s (user=%v pass=%v uris=%d fields=%d)\n", name, username != "", password != "", len(uris), len(rest))
 	return nil
 }
+
+func urisOf(pc *PlainCipher) []string { return pc.URIs }