feat(chrome): translate legacy string selectors to CSS/XPath

TapSelector now maps id:/desc:/descPrefix:/testTag:/etc. through
TranslateStringSelector. Unknown prefixes pass through to a CSS
attribute selector so a future Maestro key works without a release.

internal/driver/chrome/translate.go

@@ -0,0 +1,67 @@
+package chrome
+
+import (
+	"errors"
+	"strings"
+)
+
+// TranslateStringSelector converts a legacy string selector ("id:foo",
+// "descPrefix:bar") into a CSS selector or XPath expression usable from the
+// chrome driver's TapSelector fallback path. The boolean return is true when
+// the result is XPath rather than CSS. Unknown prefixes pass through to a CSS
+// attribute match by the same name so a Maestro-side addition (e.g. a future
+// "role:") works without a Sanderling release.
+func TranslateStringSelector(selector string) (string, bool, error) {
+	if selector == "" {
+		return "", false, errors.New("empty selector")
+	}
+	colon := strings.IndexByte(selector, ':')
+	if colon <= 0 {
+		return "", false, errors.New("selector missing prefix (expected `kind:value`)")
+	}
+	kind := selector[:colon]
+	value := selector[colon+1:]
+	switch kind {
+	case "id", "resource-id":
+		return `[id="` + cssEscape(value) + `"]`, false, nil
+	case "class":
+		return "." + cssEscape(value), false, nil
+	case "tag":
+		return cssEscape(value), false, nil
+	case "text":
+		return `//*[normalize-space(text())="` + xpathEscape(value) + `"]`, true, nil
+	case "desc", "label", "content-desc", "accessibilityLabel", "accessibilityText", "ariaLabel", "aria-label":
+		return `[aria-label="` + cssEscape(value) + `"]`, false, nil
+	case "descPrefix":
+		return `[aria-label^="` + cssEscape(value) + `"]`, false, nil
+	case "testTag", "testID", "testid", "data-testid":
+		return `[data-testid="` + cssEscape(value) + `"]`, false, nil
+	case "placeholder", "placeholderValue", "hintText":
+		return `[placeholder="` + cssEscape(value) + `"]`, false, nil
+	default:
+		return `[` + kind + `="` + cssEscape(value) + `"]`, false, nil
+	}
+}
+
+// cssEscape escapes the subset of characters that break a CSS string literal
+// inside `[attr="..."]`. Quotes and backslashes are escaped per CSSOM's
+// CSS.escape rules; other printable bytes pass through.
+func cssEscape(value string) string {
+	var builder strings.Builder
+	builder.Grow(len(value))
+	for index := 0; index < len(value); index++ {
+		c := value[index]
+		switch c {
+		case '\\', '"':
+			builder.WriteByte('\\')
+			builder.WriteByte(c)
+		default:
+			builder.WriteByte(c)
+		}
+	}
+	return builder.String()
+}
+
+func xpathEscape(value string) string {
+	return strings.ReplaceAll(value, `"`, `\"`)
+}