Standardize softwareType to lowercase everywhere

- ConfigManager.buildConfig() now lowercases softwareType
- Updated config JSON defaults to lowercase
- childRegistrationUtils lowercases softwareType on extraction
- Closes #8

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

src/helper/childRegistrationUtils.js

@@ -6,7 +6,7 @@ class ChildRegistrationUtils {
   }
 
   async registerChild(child, positionVsParent, distance) {
-    const { softwareType } = child.config.functionality;
+    const softwareType = (child.config.functionality.softwareType || '').toLowerCase();
     const { name, id } = child.config.general;
 
     this.logger.debug(`Registering child: ${name} (${id}) as ${softwareType} at ${positionVsParent}`);