Fix ESLint errors, bugs, and add gravity export

- Fix missing return in childRegistrationUtils.registerChild()
- Fix assertionUtils: assertNoNaN uses this.assertNoNaN
- Fix logger: nameModule uses this.nameModule
- Fix assetUtils: convert ESM to CommonJS
- Fix childRegistrationUtils_DEPRECATED: desc -> softwareType
- Add gravity export to index.js for rotatingMachine
- Fix ESLint errors across 18 files (no-undef, no-case-declarations,
  no-mixed-spaces-and-tabs, parsing errors)

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

src/helper/nodeTemplates.js

@@ -53,4 +53,4 @@ const nodeTemplates = {
   // …add more node “templates” here…
 };
 
-export default nodeTemplates;
+module.exports = nodeTemplates;