feat(fls): XMLEncoder reader following java.beans.XMLDecoder

A generic interpreter for the .fls configuration: objects, properties,
calls, indexes, static fields and factories, Field.set, and id/idref
anywhere — including getter results, answered from the measured Java
defaults or reported as unresolved. All 23 corpus files: class and
position of every node as Java reads them, also where Swift loses nodes.

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

packages/fls/package.json

@@ -8,6 +8,7 @@
     ".": "./src/index.ts"
   },
   "dependencies": {
-    "fflate": "^0.8.2"
+    "fflate": "^0.8.2",
+    "saxes": "^6.0.0"
   }
 }