feat(core): the firewall settings page of routers after Java, measured against Java

The page konfig changes the firewall at run time (into the snapshot, back
into the project through projectWithSimulationChanges). KonfigCases feeds
Java's plug-in directly (25 cases, de and en); RouterWebRun plays two
stories over the network. Ten Java bugs named, not adopted. The web server
answers a method not written GET or POST with 501, as Java does.

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

packages/fls/src/projectSnapshot.ts

@@ -8,6 +8,10 @@
 // echo or web server is there either way, switched on or off (it can be
 // switched at run time). The programs read the nodes' files (a web server its
 // pages).
+//
+// Back the other way: what the simulation changes that Java keeps in the
+// project (its objects are the project's), so a project saved after it holds
+// it. That is a router's or home router's firewall, set on its page konfig.
 
 import { portSnapshot, topologySnapshot, type DnsServerConfiguration, type EchoServerSnapshot, type Id, type WebServerSnapshot, type TopologySnapshot } from '@mdg-filius/core';
 import type { ImportedProject } from './importProject.js';
@@ -51,3 +55,8 @@ export function projectSnapshot(project: ImportedProject): TopologySnapshot {
     fileSystemsByNodeId: project.virtualFileSystems,
   });
 }
+
+/** The project with what the simulation changed that Java keeps: the firewalls, as the run's snapshot holds them. */
+export function projectWithSimulationChanges(project: ImportedProject, snapshot: TopologySnapshot): ImportedProject {
+  return { ...project, firewallConfigurationsByNodeId: new Map(snapshot.firewallConfigurationsByNodeId) };
+}