feat(fls): write the topology of a .fls, loaded by Java as the original

topologyWriter.ts writes konfiguration.xml from Java's view of a project:
the version line, the node items (label position, device with name,
host label flags, interfaces or ports), the cable items and the
documentation items. What a device's constructor makes is changed through
getters, as XMLEncoder does, and more is added; fewer than it makes set the
list anew. Cable ends name the port objects the getters return (the writer
now names a getter's result, <void id="Port0" property="port"/>), and each
cable carries the nodes the editor draws it between.

Checked by Java against Java: every corpus file, read and written again,
loads in Java FILIUS (the oracle's loading method, --sha256 ties its result
to the written bytes) to the same devices, names, positions, interfaces,
cables and documentation as the original; so does a synthetic topology with
what the corpus never sets. The oracle and the reader now also report a
cable's drawing ends (JCablePanel ziel1/ziel2): in the corpus the nodes it
joins, for all 183 cables. Mutation probes rewrite the files and let Java
load each mutant.

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

packages/fls/test/javaBeansWriter.test.ts

@@ -16,6 +16,7 @@ import {
   int,
   long,
   object,
+  reference,
   type BeanObject,
   type BeanValue,
 } from '../src/javaBeansWriter.js';
@@ -42,7 +43,23 @@ const file = object('filius.software.system.Datei', [
   { set: 'dateiInhalt', value: 'a.de. A 3600 1.2.3.4\n' },
 ]);
 
+const port = reference('Port');
+
 const CASES: Record<string, { values: BeanValue[]; expected: unknown[] }> = {
+  references: {
+    values: [
+      object('java.util.LinkedList', [
+        { call: 'add', args: [object('filius.hardware.NetzwerkInterface', [{ set: 'ip', value: '10.0.0.1' }, { get: 'port', statements: [], as: port }])] },
+        { call: 'add', args: [port] },
+      ]),
+    ],
+    expected: [
+      items('java.util.LinkedList', [
+        bean('filius.hardware.NetzwerkInterface', { ip: text('10.0.0.1'), port: { id: 2, class: 'filius.hardware.Port' } }),
+        { ref: 2 },
+      ]),
+    ],
+  },
   strings: {
     values: [list('java.util.LinkedList', STRINGS)],
     expected: [items('java.util.LinkedList', STRINGS.map(text))],