fix: eliminate XSS vulnerability in SetAttribute by using Playwright arg passing

Replace string interpolation in SetAttribute with Playwright's Evaluate
argument passing mechanism. This structurally eliminates the injection
surface — arbitrary name/value strings are safely passed as JavaScript
arguments rather than interpolated into the expression string.

The vulnerable escapeJavaScript helper (which only escaped \ and ') is
removed since it is no longer needed.

Closes #12

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

node.go

@@ -2,7 +2,6 @@ package extractor
 
 import (
 	"fmt"
-	"strings"
 
 	"github.com/playwright-community/playwright-go"
 )
@@ -104,11 +103,10 @@ func (n node) SetHidden(val bool) error {
 	return nil
 }
 
-func escapeJavaScript(s string) string {
-	return strings.Replace(strings.Replace(s, "\\", "\\\\", -1), "'", "\\'", -1)
-}
-
 func (n node) SetAttribute(name, value string) error {
-	_, err := n.locator.Evaluate(fmt.Sprintf(`(element) => element.setAttribute('%s', '%s');`, escapeJavaScript(name), escapeJavaScript(value)), nil)
+	_, err := n.locator.Evaluate(
+		`(element, args) => element.setAttribute(args.name, args.value)`,
+		map[string]string{"name": name, "value": value},
+	)
 	return err
 }