feat: add native Windows hierarchy test harness

internal/config/config_test.go

@@ -49,6 +49,17 @@ func TestAnnotatedExamples_HP_CFG_01(t *testing.T) {
 	}
 }
 
+func TestClientDefaultsDecodeForWindowsWithoutNativeFilesystem(t *testing.T) {
+	t.Parallel()
+	client, err := DecodeClient([]byte("[client]\nstate_dir = \"C:\\\\ProgramData\\\\RVBox\\\\state\"\ndaemon_cwd = \"C:\\\\ProgramData\\\\RVBox\\\\work\"\n"), ClientOptions{Platform: PlatformWindows, CheckFilesystem: false})
+	if err != nil {
+		t.Fatalf("DecodeClient Windows defaults: %v", err)
+	}
+	if client.Shells.SH != "/bin/sh" || client.Shells.CMD == "" {
+		t.Fatalf("Windows defaults have unexpected shell paths: %+v", client.Shells)
+	}
+}
+
 func TestStrictTOMLRejections_HP_CFG_01(t *testing.T) {
 	t.Parallel()
 

internal/config/path.go

@@ -3,6 +3,7 @@ package config
 import (
 	"fmt"
 	"os"
+	"path"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -21,10 +22,13 @@ func validateAbsolutePath(name, value string, platform Platform, allowEmpty bool
 		}
 		return cleanWindowsPath(value), nil
 	}
-	if !filepath.IsAbs(value) {
+	// Config parsing can validate an inactive Unix shell path while running on
+	// Windows. filepath follows the host OS, whereas the config field's stated
+	// platform is Unix, so use slash-path semantics here.
+	if !path.IsAbs(value) {
 		return "", fmt.Errorf("%s must be an absolute Unix path", name)
 	}
-	return filepath.Clean(value), nil
+	return path.Clean(value), nil
 }
 
 func isWindowsAbsolute(value string) bool {