feat(fls): system software settings as Java loads them

readSystemSoftware adds to each node what the topology needs from its
system software: a switch's SSID and learning time, a host's wireless
SSID, a router's RIP switch, the manual routes and the firewall of a
router or home router. All 23 corpus files match Java.

- A router's firewall is one object its constructor hangs in two places;
  the corpus writes it under the web server's "konfig" plug-in. The
  places are merged.
- The decoder keeps entries a constructor made in a map, reached by
  get(key) (installed applications), like the elements of a list.
- The Java oracle loads every file twice and writes values that differ
  as null: what FILIUS rolls (MACs, a switch's SSID) without text search.

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

packages/fls/src/javabeans.ts

@@ -53,6 +53,11 @@ export interface JavaObject {
    * result. `add`/`set` go to `calls`, in order.
    */
   readonly presetElements: Map<number, JavaValue>;
+  /**
+   * The same for a map: entries its constructor made (a router's installed
+   * applications), reached by `<void method="get"><string>key</string>`.
+   */
+  readonly presetEntries: Map<string, JavaValue>;
   /** True when the object was not in the file but returned by a getter. */
   readonly fromGetter: boolean;
 }
@@ -139,12 +144,21 @@ function replayList(value: JavaObject, constructed: number): (JavaValue | undefi
   return items;
 }
 
-/** The entries of a map: `put` calls in order. */
+/**
+ * The entries of a map: the ones its constructor made, then `put` calls in
+ * order — a later `put` of the same key replaces the value in place.
+ */
 export function mapEntries(value: JavaValue | undefined): [JavaValue, JavaValue][] {
   if (!isJavaObject(value)) return [];
-  return value.calls
-    .filter((call) => call.method === 'put')
-    .map((call) => [call.args[0] ?? null, call.args[1] ?? null] as [JavaValue, JavaValue]);
+  const entries: [JavaValue, JavaValue][] = [...value.presetEntries];
+  for (const call of value.calls) {
+    if (call.method !== 'put') continue;
+    const key = call.args[0] ?? null;
+    const existing = entries.find(([entryKey]) => entryKey === key);
+    if (existing === undefined) entries.push([key, call.args[1] ?? null]);
+    else existing[1] = call.args[1] ?? null;
+  }
+  return entries;
 }
 
 // ── XML tree ───────────────────────────────────────────────────────────────
@@ -226,6 +240,7 @@ function newObject(fields: Partial<JavaObject> & { className: string }): JavaObj
     properties: new Map(),
     calls: [],
     presetElements: new Map(),
+    presetEntries: new Map(),
     fromGetter: fields.fromGetter ?? false,
   };
 }
@@ -412,6 +427,7 @@ class Decoder {
     if (isJavaObject(target)) {
       target.calls.push({ method, args });
       if (method === 'get' && args.length === 1 && typeof args[0] === 'number') return this.getIndex(target, args[0], id);
+      if (method === 'get' && args.length === 1 && typeof args[0] === 'string') return this.getEntry(target, args[0], id);
     }
     return null;
   }
@@ -463,6 +479,18 @@ class Decoder {
     return placeholder;
   }
 
+  /**
+   * `map.get(key)`: the value put before, else an entry the map held before
+   * the file touched it — a placeholder that later reads return.
+   */
+  private getEntry(target: JavaObject, key: string, id: string | undefined): JavaValue {
+    const put = mapEntries(target).find(([entryKey]) => entryKey === key);
+    if (put !== undefined) return put[1];
+    const placeholder = newObject({ className: id?.replace(/\d+$/, '') ?? 'unknown', id, fromGetter: true });
+    target.presetEntries.set(key, placeholder);
+    return placeholder;
+  }
+
   private setIndex(target: JavaValue | undefined, index: number, value: JavaValue): JavaValue {
     if (typeof target === 'object' && target !== null && (target as JavaArray).kind === 'array') {
       (target as JavaArray).items[index] = value;