docs(0001e): note remaining gateway and unibots migration

The web gateway (playground) and unibots (in the agents repo) are not migrated
here: the gateway stays a local dev tool at AuthOff, and the bot transport
lives outside this sub-repo. dev/0001e-remaining-clients.md records exactly
what each needs (client.Connect with ca.crt, identity registered in the
allowlist) and the operator server flags for phase 0001f.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

playground/server.go

@@ -861,7 +861,8 @@ func main() {
 		log.Fatalf("open blob store: %v", err)
 	}
 	// AuthOff: the playground is a local dev gateway that has not migrated to
-	// signed control-plane requests yet (tracked in phase 0001e of issue 0001).
+	// signed control-plane requests or a secured upstream bus yet. What it would
+	// need is written up in dev/0001e-remaining-clients.md (issue 0001, phase 0001e).
 	ctrlSrv := &http.Server{Addr: ctrlAddr, Handler: membership.NewServer(store, blobs, membership.AuthOff)}
 	go func() {
 		if err := ctrlSrv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {