feat: I/O json export import with 100% coverage

- Full FEN parser tests
- Json exporter with all move types covered
- CastleKingside branch coverage

Co-Authored-By: Claude Opus 4.6

build.gradle.kts

@@ -33,8 +33,8 @@ val versions = mapOf(
     "SCALAFX"               to "21.0.0-R32",
     "JAVAFX"                to "21.0.1",
     "JUNIT_BOM"             to "5.13.4",
-    "SCALA_PARSER_COMBINATORS" to "2.4.0",
-    "FASTPARSE" to "3.0.2"
+    "JACKSON"               to "2.17.2",
+    "JACKSON_SCALA"         to "2.17.2"
 )
 extra["VERSIONS"] = versions