fix: builder and sdk changes (#81)

## Description

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At least please give us some description what you are trying to achieve and why your change is needed. -->

relates to #1234

## Checklist

- [ ] Issue was linked above
- [ ] Code format was applied: `make fmt`
- [ ] Examples were added / adjusted (see `examples/` directory)
- [x] Docs are up-to-date: `make generate-docs` (will be checked by CI)
- [ ] Unit tests got implemented or updated
- [ ] Acceptance tests got implemented or updated (see e.g. [here](f5f99d1709/stackit/internal/services/dns/dns_acc_test.go))
- [x] Unit tests are passing: `make test` (will be checked by CI)
- [x] No linter issues: `make lint` (will be checked by CI)

Co-authored-by: Marcel S. Henselin <marcel.henselin@stackit.cloud>
Co-authored-by: marcel.henselin <marcel.henselin@stackit.cloud>
Reviewed-on: #81

generator/cmd/build/copy.go

@@ -0,0 +1,131 @@
+package build
+
+import (
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// Source - https://stackoverflow.com/a
+// Posted by Oleg Neumyvakin, modified by community. See post 'Timeline' for change history
+// Retrieved 2026-01-20, License - CC BY-SA 4.0
+
+func CopyDirectory(scrDir, dest string) error {
+	entries, err := os.ReadDir(scrDir)
+	if err != nil {
+		return err
+	}
+	for _, entry := range entries {
+		sourcePath := filepath.Join(scrDir, entry.Name())
+		destPath := filepath.Join(dest, entry.Name())
+
+		fileInfo, err := os.Stat(sourcePath)
+		if err != nil {
+			return err
+		}
+
+		stat, ok := fileInfo.Sys().(*syscall.Stat_t)
+		if !ok {
+			return fmt.Errorf("failed to get raw syscall.Stat_t data for '%s'", sourcePath)
+		}
+
+		switch fileInfo.Mode() & os.ModeType {
+		case os.ModeDir:
+			if err := CreateIfNotExists(destPath, 0o755); err != nil {
+				return err
+			}
+			if err := CopyDirectory(sourcePath, destPath); err != nil {
+				return err
+			}
+		case os.ModeSymlink:
+			if err := CopySymLink(sourcePath, destPath); err != nil {
+				return err
+			}
+		default:
+			if err := Copy(sourcePath, destPath); err != nil {
+				return err
+			}
+		}
+
+		if err := os.Lchown(destPath, int(stat.Uid), int(stat.Gid)); err != nil {
+			return err
+		}
+
+		fInfo, err := entry.Info()
+		if err != nil {
+			return err
+		}
+
+		isSymlink := fInfo.Mode()&os.ModeSymlink != 0
+		if !isSymlink {
+			if err := os.Chmod(destPath, fInfo.Mode()); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func Copy(srcFile, dstFile string) error {
+	out, err := os.Create(dstFile)
+	if err != nil {
+		return err
+	}
+
+	defer func(out *os.File) {
+		err := out.Close()
+		if err != nil {
+			slog.Error("failed to close file", slog.Any("err", err))
+		}
+	}(out)
+
+	in, err := os.Open(srcFile)
+	if err != nil {
+		return err
+	}
+
+	defer func(in *os.File) {
+		err := in.Close()
+		if err != nil {
+			slog.Error("error closing destination file", slog.Any("err", err))
+		}
+	}(in)
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func Exists(filePath string) bool {
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		return false
+	}
+
+	return true
+}
+
+func CreateIfNotExists(dir string, perm os.FileMode) error {
+	if Exists(dir) {
+		return nil
+	}
+
+	if err := os.MkdirAll(dir, perm); err != nil {
+		return fmt.Errorf("failed to create directory: '%s', error: '%s'", dir, err.Error())
+	}
+
+	return nil
+}
+
+func CopySymLink(source, dest string) error {
+	link, err := os.Readlink(source)
+	if err != nil {
+		return err
+	}
+	return os.Symlink(link, dest)
+}