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>

index.js

@@ -26,6 +26,13 @@ const predict = require('./src/predict/predict_class.js');
 const interpolation = require('./src/predict/interpolation.js');
 const childRegistrationUtils = require('./src/helper/childRegistrationUtils.js');
 const { loadCurve } = require('./datasets/assetData/curves/index.js');
+const Fysics = require('./src/convert/fysics.js');
+
+// Gravity helper (used by rotatingMachine for efficiency calculations)
+const gravity = {
+    getStandardGravity: () => 9.80665,
+    fysics: new Fysics()
+};
 
 // Export everything
 module.exports = {
@@ -44,5 +51,6 @@ module.exports = {
     convert,
     MenuManager,
     childRegistrationUtils,
-    loadCurve
+    loadCurve,
+    gravity
 };