Fix false positive: don't flag this in class component templates

The rule was incorrectly flagging `this` usage in ALL `<template>` tags,
including those inside class bodies (class components). It should only
flag `this` in template-only components (standalone `<template>` tags).

Also adds missing BUILTIN_PROPERTIES from the original ember-template-lint
rule: action, element, parentView, attrs, isDestroying, isDestroyed.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Author: NullVoxPopuli

lib/rules/template-no-this-in-template-only-components.js

@@ -24,6 +24,10 @@ module.exports = {
   create(context) {
     // Properties that should not be auto-fixed (built-in component properties)
     const BUILTIN_PROPERTIES = new Set([
+      'action',
+      'element',
+      'parentView',
+      'attrs',
       'elementId',
       'tagName',
       'ariaRole',
@@ -32,10 +36,26 @@ module.exports = {
       'classNameBindings',
       'attributeBindings',
       'isVisible',
+      'isDestroying',
+      'isDestroyed',
     ]);
 
     return {
       GlimmerPathExpression(node) {
+        // Only flag template-only components, not class components.
+        // Walk ancestors to check if the <template> is inside a class body.
+        const sourceCode = context.sourceCode ?? context.getSourceCode();
+        const ancestors = sourceCode.getAncestors
+          ? sourceCode.getAncestors(node)
+          : context.getAncestors();
+        const isInsideClass = ancestors.some(
+          (ancestor) =>
+            ancestor.type === 'ClassBody' || ancestor.type === 'ClassDeclaration'
+        );
+        if (isInsideClass) {
+          return;
+        }
+
         // In gjs/gts files with <template> tags, check for this.* usage
         if (node.head?.type === 'ThisHead' && node.tail?.length > 0) {
           const original = node.original;

tests/lib/rules/template-no-this-in-template-only-components.js

@@ -12,6 +12,9 @@ ruleTester.run('template-no-this-in-template-only-components', rule, {
     '<template><WelcomePage /></template>',
     '<template><MyComponent @prop={{can "edit" @model}} /></template>',
     '<template>{{my-component model=model}}</template>',
+    // Class components should not be flagged (not template-only)
+    'class MyComponent extends Component { <template>{{this.foo}}</template> }',
+    'class MyComponent extends Component { <template>{{this.bar}} {{this.baz}}</template> }',
   ],
   invalid: [
     {