Use a portable version of addSlash

internal/dav/util.go

@@ -1,14 +1,22 @@
 package dav
 
 import (
-	"path/filepath"
 	"strings"
 )
 
+// addSlash ensures the input string ends with a slash regardless of the OS
 func addSlash(input string) string {
-	p := filepath.Join("/", input)
-	if p == "/" || strings.HasSuffix(p, "/") {
-		return p
+	// Standardize the path separator to use forward slashes
+	input = strings.ReplaceAll(input, "\\", "/")
+
+	// Ensure the input starts with a slash
+	if !strings.HasPrefix(input, "/") {
+		input = "/" + input
 	}
-	return p + "/"
+
+	// Ensure the path ends with a slash
+	if !strings.HasSuffix(input, "/") {
+		input += "/"
+	}
+	return input
 }