fix: stop throttling the realtime subscribe proxy

Centrifugo calls the proxy from 127.0.0.1 for every client, so the
per-IP fallback put every subscribe into one bucket that any token
holder could exhaust. Throttle only the token route, per user.

routes.go

@@ -30,8 +30,9 @@ const (
 	// bucketManage throttles the management API per token, or per client IP
 	// for a request without one.
 	bucketManage = "throttle:jz.bm.manage"
-	// bucketRealtime throttles the realtime token and subscribe-proxy
-	// routes per user, or per client IP for a request without one.
+	// bucketRealtime throttles the realtime token route per user (it runs
+	// after jwt.auth), or per client IP for a request without one. The
+	// subscribe proxy is not throttled: see mountRealtime.
 	bucketRealtime = "throttle:jz.bm.realtime"
 )
 
@@ -154,16 +155,21 @@ func (p *Plugin) Routes(r pact.Router) error {
 // of golem15.presentations is the only realtime consumer, so nothing is
 // mounted without it, and the token route is limited to presentation owners
 // by its presentations.realtime-owner guard, named here without importing
-// the plugin. Routes built without Boot (bare tests) mount nothing; the
-// default null driver declares no routes.
+// the plugin. Only the token route is throttled, per user. The subscribe
+// proxy is called by Centrifugo from 127.0.0.1 for every client, so any
+// throttle there would be one shared bucket that a single token holder
+// could exhaust and lock the owner out; it relies on its constant-time
+// secret check and Centrifugo's own limits instead. Routes built without
+// Boot (bare tests) mount nothing; the default null driver declares no
+// routes.
 func (p *Plugin) mountRealtime(r pact.Router) error {
 	if p.realtime == nil || p.app == nil || !p.app.HasPlugin("golem15.presentations") {
 		return nil
 	}
 	return lighthouse.Mount(r, p.realtime.Driver(), lighthouse.Surfaces{
-		UserAuth:       surf.Use("jwt.auth", "presentations.realtime-owner"),
+		UserAuth:       surf.Use("jwt.auth", "presentations.realtime-owner", bucketRealtime),
 		ServerToServer: surf.Use(),
-		Middleware:     surf.Use(bucketRealtime),
+		Middleware:     surf.Use(),
 	})
 }