feat(config): add Scaffolding.Boards typed input with 6 defaults

internal/config/config_test.go

@@ -108,3 +108,26 @@ func TestLoadRejectsUnknownVersion(t *testing.T) {
 		t.Fatal("expected version error")
 	}
 }
+
+func TestDefaultsCarryScaffoldingBoards(t *testing.T) {
+	cfg, err := Load("/nonexistent/overlay.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(cfg.Scaffolding.Boards) < 6 {
+		t.Fatalf("want >= 6 boards, got %d", len(cfg.Scaffolding.Boards))
+	}
+	want := map[string]string{
+		"uno": "arduino:avr:uno", "mega": "arduino:avr:mega", "nano": "arduino:avr:nano",
+		"esp32": "esp32:esp32:esp32", "esp32s3": "esp32:esp32:esp32s3", "esp8266": "esp8266:esp8266:nodemcuv2",
+	}
+	got := map[string]string{}
+	for _, b := range cfg.Scaffolding.Boards {
+		got[b.Name] = b.FQBN
+	}
+	for name, fqbn := range want {
+		if got[name] != fqbn {
+			t.Errorf("board %q: got fqbn %q, want %q", name, got[name], fqbn)
+		}
+	}
+}