fix: prevent infinite recursion in validateSchema for non-object schema entries

migrateConfig stamps a version string into config schemas. validateSchema
then iterates the string's character indices, causing infinite recursion.
Skip the 'version' key and guard against any non-object schema entries.

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

src/helper/validationUtils.js

@@ -95,11 +95,19 @@ class ValidationUtils {
         // Validate each key in the schema and loop over wildcards if they are not in schema
         for ( const key in schema ) {
 
-            if (key === "rules" || key === "description" || key === "schema") {
+            if (key === "rules" || key === "description" || key === "schema" || key === "version") {
                 continue;
               }
 
             const fieldSchema = schema[key];
+
+            // Skip non-object schema entries (e.g. primitive values injected by migration)
+            if (fieldSchema === null || typeof fieldSchema !== 'object') {
+                this.logger.debug(`${name}.${key} has a non-object schema entry (${typeof fieldSchema}). Skipping.`);
+                validatedConfig[key] = fieldSchema;
+                continue;
+            }
+
             const { rules = {} } = fieldSchema;
 
             // Default to the schema's default value if the key is missing