Read wpak cfgs from one folder per archive

Files now load from mb.data/wpak/<archive>/<file>, matching MBDATA's
data/wpak layout and the client's Config/Config.wpak naming, so more
archives can sit beside Config/ later. All nine current files are in
wpak/Config/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/engine/parsers/wpak/PowActionCostParser.java

@@ -19,7 +19,7 @@ import java.util.HashMap;
 
 public class PowActionCostParser {
 
-    private static final String fileName = "PowActionCostInfo.cfg";
+    private static final String fileName = "Config/PowActionCostInfo.cfg";
 
     public static HashMap<String, PowActionCostTemplate> parsePowActionCostFile() {