feat(sim): F4.6f1 what a run leaves goes back into the document

The oracle SaveAfterRunRun saves Java's project after a run. The room writes
what a run leaves that Java keeps - files, running servers, virtual hosts,
mail servers' domains and accounts, mail programs' accounts and folders,
firewalls, DHCP clients' addresses - into the document as origin 'sim', at
most once a second, after each action and at the stop; writeRunState writes
only what differs. The command line now goes on in a folder made before a
restart, as Java's does.

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

packages/core/test/virtualFileSystem.test.ts

@@ -164,3 +164,24 @@ describe('virtual file system', () => {
     expect(fileSystem.upgradeLegacyDefaultImages()).toBe(0);
   });
 });
+
+describe("a file system's revision", () => {
+  it('changes with every change, a removal too, and not with a reading', () => {
+    const files = new VirtualFileSystem();
+    const seen = [files.revision];
+    files.createDirectory('/a');
+    seen.push(files.revision);
+    files.writeTextFile('/a/b.txt', 'x');
+    seen.push(files.revision);
+    files.renameInPlace('/a/b.txt', 'c.txt');
+    seen.push(files.revision);
+    files.deleteItem('/a/c.txt');
+    seen.push(files.revision);
+    files.allEntries();
+    files.contains('/a');
+    seen.push(files.revision);
+    expect(new Set(seen.slice(0, 5)).size).toBe(5);
+    expect(seen[5]).toBe(seen[4]);
+  });
+});
+