feat: improve field type mapping and add sample dataset resource

- Update GUtils.java to handle case-insensitive column type mapping.
- Add "number" type mapping to support more database dialects.
- Add DevResources/Dataset.xml as a sample dataset definition.

src/main/java/com/sdk/generators/GUtils.java

@@ -34,6 +34,7 @@ public class GUtils {
         TYPE_MAPPING.put("float", "NUMBER");
         TYPE_MAPPING.put("integer", "NUMBER");
         TYPE_MAPPING.put("numeric", "NUMBER");
+        TYPE_MAPPING.put("number", "NUMBER");
         TYPE_MAPPING.put("smallint", "NUMBER");
         TYPE_MAPPING.put("timestamp", "DATE");
         TYPE_MAPPING.put("text", "STRING");
@@ -80,7 +81,7 @@ public class GUtils {
 
     public static String getFieldType(DasColumn column) {
         String columnType = column.getDasType().toDataType().typeName;
-        String fieldType = TYPE_MAPPING.get(columnType);
+        String fieldType = TYPE_MAPPING.get(columnType.toLowerCase());
         if (fieldType == null) {
             fieldType = TYPE_MAPPING.getOrDefault(userDefType.getOrDefault(columnType, "varchar"), "Object");
         }