make bucket-scan wordlist opt-in (default off)

Discovery is now driven purely by incoming CT domains (stem + suffix
expansion); the hardcoded generic-name wordlist is only used when
BUCKET_SCAN_WORDLIST=true.

cmd/ctcloud/main.go

@@ -167,12 +167,16 @@ func run() error {
 			},
 		})
 		discoverer.Start(ctx)
-		for _, name := range discover.Wordlist() {
-			discoverer.SubmitName(name)
+		wordlist := 0
+		if cfg.BucketScanWordlist {
+			for _, name := range discover.Wordlist() {
+				discoverer.SubmitName(name)
+			}
+			wordlist = len(discover.Wordlist())
 		}
 		slog.Info("bucket name discovery enabled", "event", "startup",
 			"qps", cfg.BucketScanQPS, "workers", cfg.BucketScanWorkers, "do_spaces", cfg.BucketScanDO,
-			"wordlist", len(discover.Wordlist()))
+			"wordlist", wordlist)
 	}
 
 	var prober *probe.Prober