Add goTool autotest with bench configs and UART scenarios.

JSON configs describe network and node MACs; scenarios run command
sequences with expect checks. Share UART client API across CLI and tests.

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

goTool/autotest/config_test.go

@@ -0,0 +1,29 @@
+package autotest
+
+import "testing"
+
+func TestNewBenchClientIDFromMAC(t *testing.T) {
+	cfg := Config{
+		ID:        "t",
+		Network:   1,
+		MasterMAC: "aa:bb:cc:dd:ee:ff",
+		Slaves: []SlaveNode{{
+			ID:  "pod",
+			MAC: "50:78:7d:18:01:10",
+		}},
+	}
+	b, err := NewBench(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s, _ := b.Slave("pod")
+	if *s.ClientID != 16 {
+		t.Fatalf("client_id=%d want 16", *s.ClientID)
+	}
+}
+
+func TestMACEqual(t *testing.T) {
+	if !MACEqual("50:78:7D:18:01:10", "50-78-7d-18-01-10") {
+		t.Fatal("MACEqual failed")
+	}
+}