feat(editor): F4.6e the e-mail program and e-mail server on a computer's desktop

The oracle MailWindowRun uses Java's e-mail windows as a person does and
answers their dialogs. The core sets and saves the program's account,
deletes a mail, checks a form as Java's window does, and gives the server
its domain, new and removed accounts and the window's own line; the room
sends both programs' views and takes their actions; the editor has both
windows. Better than Java: a name field for a new account, a user name the
server has is refused, deleting hits the folder shown, a new domain goes
into the accounts file at once.

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

packages/core/src/runtime/engine.ts

@@ -124,7 +124,7 @@ import { Terminal } from './apps/terminal.js';
 import { firewallLogPage, forwardingTablePage, ripTablePage, routerIndexPage } from './apps/routerPages.js';
 import { applyFirewallSettings, firewallSettingsPage } from './apps/firewallSettings.js';
 import { parentPath, VirtualFileSystem } from '../model/virtualFileSystem.js';
-import { EMAIL_SERVER_ACCOUNTS_FILE, serverAccountsFileText } from './emailAccountsFile.js';
+import { clientAccountFileText, EMAIL_CLIENT_ACCOUNT_FILE, EMAIL_SERVER_ACCOUNTS_FILE, serverAccountsFileText } from './emailAccountsFile.js';
 import { GNUTELLA_FOLDER, GnutellaPeer } from './apps/gnutella.js';
 import {
   PRODUCTION_TRACE_RETENTION,
@@ -1203,18 +1203,19 @@ export class NetworkRuntimeEngine {
   }
 
   /** An e-mail server's accounts as a run changed them, into the snapshot (and so into the project saved from it). */
-  private setEmailServerAccounts(nodeId: Id, accounts: readonly EmailServerAccount[]): void {
+  private setEmailServerAccounts(nodeId: Id, accounts: readonly EmailServerAccount[], domain: string): void {
     const servers = new Map(this.stateValue.topologySnapshot.emailServersByNodeId);
     const server = servers.get(nodeId);
     if (server === undefined) return;
-    servers.set(nodeId, { ...server, accounts });
+    servers.set(nodeId, { ...server, accounts, domain });
     this.stateValue.topologySnapshot = withSnapshot(this.stateValue.topologySnapshot, { emailServersByNodeId: servers });
-    this.writeEmailServerAccountsFile(nodeId, server.domain, accounts);
+    this.writeEmailServerAccountsFile(nodeId, domain, accounts);
   }
 
   /**
    * The server's account file (EmailServer.kontenSpeichern), written from its
-   * accounts at its start and whenever they change. Java makes it empty at
+   * accounts at its start and whenever they or its domain change (Java writes
+   * a new domain only with the next change of its accounts). Java makes it empty at
    * its start when it is missing (and reads it), and writes it when an
    * account is made or removed, after a POP3 command, after an SMTP mail was
    * taken and when it stops — but before the notice to a local sender, which
@@ -1305,7 +1306,7 @@ export class NetworkRuntimeEngine {
             this,
             nodeId,
             emailServer,
-            (accounts) => this.setEmailServerAccounts(nodeId, accounts),
+            (accounts, domain) => this.setEmailServerAccounts(nodeId, accounts, domain),
             () => this.networkInterfaces(nodeId)[0]?.ipAddress ?? 'null',
             this.wallClock,
           ),
@@ -1324,7 +1325,16 @@ export class NetworkRuntimeEngine {
         return;
       }
       case 'emailClient':
-        this.emailClientsByNodeId.set(nodeId, new EmailClient(this, nodeId, snapshot.emailClientsByNodeId.get(nodeId)!, (folders) => this.setEmailClientFolders(nodeId, folders)));
+        this.emailClientsByNodeId.set(
+          nodeId,
+          new EmailClient(
+            this,
+            nodeId,
+            snapshot.emailClientsByNodeId.get(nodeId)!,
+            (folders) => this.setEmailClientFolders(nodeId, folders),
+            (account) => this.nodeFiles(nodeId).writeTextFile(EMAIL_CLIENT_ACCOUNT_FILE, clientAccountFileText(account)),
+          ),
+        );
         return;
     }
   }