Release 3.8.1.1: lighter idle UI poll, core cache, multicore ping.

Reduce idle CPU (cheap PollUI, binary cache, logbuf cap, DOM fingerprint),
speed ping/AWG HostPort, CopyBuffer pool; ship arm64 build and update notes.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/protocols/awg/conf_test.go

@@ -236,3 +236,29 @@ func indexOf(s, sub string) int {
 	}
 	return -1
 }
+
+func TestHostPortLightINI(t *testing.T) {
+	raw := `[Interface]
+PrivateKey = AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
+Address = 10.8.0.2/32
+
+[Peer]
+PublicKey = AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEE=
+Endpoint = 203.0.113.10:51820
+AllowedIPs = 0.0.0.0/0
+`
+	h, p, err := HostPort(raw)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if h != "203.0.113.10" || p != "51820" {
+		t.Fatalf("got %s:%s", h, p)
+	}
+	h2, p2, err := HostPort("awg://AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=@9.9.9.9:41421")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if h2 != "9.9.9.9" || p2 != "41421" {
+		t.Fatalf("uri got %s:%s", h2, p2)
+	}
+}