Handle missing absolutePaths for ember-source v7+

ember-source v7 no longer exports `absolutePaths` from its addon entry
point. Fall back to resolving the template compiler through the package
exports map when `absolutePaths` is absent.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: NullVoxPopuli

lib/ember-addon-main.js

@@ -105,7 +105,13 @@ module.exports = {
       );
     }
 
-    return ember.absolutePaths.templateCompiler;
+    if (ember.absolutePaths) {
+      return ember.absolutePaths.templateCompiler;
+    }
+
+    // v7+ ember-source no longer provides absolutePaths; resolve through
+    // the package exports map
+    return require.resolve('ember-source/ember-template-compiler/index.js');
   },
 
   astPlugins() {