fix: handle non-standard field casing in MapContains queries

Modified processMapContainsQuery to support Map fields with uppercase/non-standard casing
(e.g., 'Positions' instead of 'positions'). The method now tries both the standard
lowercase naming convention and the original field name when resolving Map fields.

This fixes repository methods like findByPositionsMapContainsCusip when the Java field
uses non-standard casing to match JSON data from external sources like RIOT exports.

Author: bsbodden

redis-om-spring/src/main/java/com/redis/om/spring/repository/query/RediSearchQuery.java

@@ -424,12 +424,25 @@ private void processMapContainsQuery(String methodName) {
           String nestedFieldName = matcher.group(2);
           String operator = matcher.group(3);
 
-          // Convert to lowercase first character
+          // Store original field name before converting
+          String originalMapFieldName = mapFieldName;
+
+          // Convert to lowercase first character for standard Java naming
           mapFieldName = Character.toLowerCase(mapFieldName.charAt(0)) + mapFieldName.substring(1);
           nestedFieldName = Character.toLowerCase(nestedFieldName.charAt(0)) + nestedFieldName.substring(1);
 
-          // Find the Map field
+          // Find the Map field - try both lowercase and original casing
           Field mapField = ReflectionUtils.findField(domainType, mapFieldName);
+          if (mapField == null) {
+            // Try with original casing (e.g., "Positions" instead of "positions")
+            mapField = ReflectionUtils.findField(domainType, originalMapFieldName);
+            if (mapField != null) {
+              // Use the actual field name for building the query
+              mapFieldName = originalMapFieldName;
+            }
+          }
+          logger.debug(String.format("Looking for Map field '%s' (or '%s') in %s: %s", mapFieldName,
+              originalMapFieldName, domainType.getSimpleName(), mapField != null ? "FOUND" : "NOT FOUND"));
           if (mapField != null && Map.class.isAssignableFrom(mapField.getType())) {
             // Get the Map's value type
             Optional<Class<?>> maybeValueType = ObjectUtils.getMapValueClass(mapField);