fix: 上行分发前统一限速，send 不再单独扣桶

internal/app/message/rate_test.go

@@ -0,0 +1,22 @@
+package message
+
+import (
+	"testing"
+)
+
+func TestAllowRequestBurstAndAckExemptBucket(t *testing.T) {
+	t.Parallel()
+	lim := defaultTestLimits()
+	lim.RequestsPerSecond = 50
+	lim.RequestBurst = 100
+	app, _ := openTestApp(t, lim)
+	allowed := 0
+	for i := 0; i < 150; i++ {
+		if app.AllowRequest("alice") {
+			allowed++
+		}
+	}
+	if allowed != 100 {
+		t.Fatalf("allowed=%d want 100 (burst)", allowed)
+	}
+}