feat: support explicit instance data deletion

internal/platform/files/reparse_windows_test.go

@@ -0,0 +1,32 @@
+//go:build windows
+
+package files
+
+import (
+	"context"
+	"errors"
+	"os"
+	"syscall"
+	"testing"
+)
+
+func TestInstanceDataRemoverRejectsWindowsReparsePoint(t *testing.T) {
+	called := false
+	remover := newInstanceDataRemover(func(string) (os.FileInfo, error) {
+		return fakeFileInfo{
+			mode: os.ModeDir,
+			sys:  &syscall.Win32FileAttributeData{FileAttributes: syscall.FILE_ATTRIBUTE_REPARSE_POINT},
+		}, nil
+	}, func(string) error {
+		called = true
+		return nil
+	})
+
+	err := remover.RemoveInstanceData(context.Background(), `C:\profiles\junction`)
+	if !errors.Is(err, ErrUnsafeInstanceDataDirectory) {
+		t.Fatalf("RemoveInstanceData() error = %v, want unsafe directory", err)
+	}
+	if called {
+		t.Fatal("reparse point reached removal")
+	}
+}