feat: wire gui instance start and delete confirmation

internal/platform/browser/launch.go

@@ -116,7 +116,10 @@ func BuildArgs(spec domain.LaunchSpec) ([]string, error) {
 		}
 		args = append(args, extra)
 	}
-	return append(args, normalized.TargetURL), nil
+	if normalized.TargetURL != "" {
+		args = append(args, normalized.TargetURL)
+	}
+	return args, nil
 }
 
 func normalizeProxy(value string) (string, error) {

internal/platform/browser/launch_test.go

@@ -48,6 +48,18 @@ func TestBuildArgsRejectsProxyCredentialsAndUnsupportedValues(t *testing.T) {
 	}
 }
 
+func TestBuildArgsAllowsDefaultBrowserPage(t *testing.T) {
+	profile := filepath.Join(t.TempDir(), "profile")
+	args, err := BuildArgs(domain.LaunchSpec{Kind: domain.BrowserChrome, UserDataDir: profile})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{"--user-data-dir=" + filepath.Clean(profile), "--no-first-run", "--disable-default-apps"}
+	if !reflect.DeepEqual(args, want) {
+		t.Fatalf("args = %#v, want %#v", args, want)
+	}
+}
+
 func TestDiscovererResolvesConfiguredAndStandardPaths(t *testing.T) {
 	root := t.TempDir()
 	chrome := filepath.Join(root, `Google\Chrome\Application\chrome.exe`)