fix(#54): address round-2 Copilot review (lowercase tag for case-insensitive HTML match)

Author: johanrd

lib/rules/template-require-mandatory-role-attributes.js

@@ -55,7 +55,9 @@ function getStaticAttrValue(node, name) {
 
 function getTagName(node) {
   if (node?.type === 'GlimmerElementNode') {
-    return node.tag;
+    // HTML tag names are case-insensitive; normalize so <INPUT>/<Input> match
+    // the lowercase keys in AX_CONCEPTS_BY_TAG and the semantic-role maps.
+    return node.tag?.toLowerCase();
   }
   if (node?.type === 'GlimmerMustacheStatement' && node.path?.original === 'input') {
     // The classic `{{input}}` helper renders a native <input>.