feat(fls): import the e-mail programs into the editor model

The e-mail client and server of every host come into the model (core:
EmailClientConfiguration, EmailServerConfiguration, EmailMessage), from
Java's view:

- the server's accounts are those of /mailserver/konten.txt, as Java reads
  them at every simulation start; without the file those of the bean list,
  which Java would drop;
- the client's account is that of /konten.txt; without it the first of an
  older file's kontoListe, which FILIUS 2.14 no longer reads;
- messages are numbered per program in folder order, as Swift does; the
  sent folder's are sent; a date is taken only when the file gives one.

Departures from Swift: accounts and messages stay where Swift drops what
fails its checks; first and last name stay apart; a port that is no number
is the default, with a warning. On the corpus the model matches Swift's on
all 13 files; the one Swift error is named (it numbers a mailbox's messages
as their received time and writes that into the konten.txt it rewrites).

The Swift dump now carries the e-mail state, and the file system
comparison leaves out only Swift's hidden state files (and the directories
it makes for them) instead of all of /mail, /mailserver and /peer2peer.

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

tools/swift-oracle/Sources/Oracle/main.swift

@@ -404,6 +404,30 @@ func describeSystem(_ state: TopologyEditorState, _ node: TopologyNode) -> JSON
             "records": dns.typedRecords.map { dnsRecordJSON($0) },
         ] as JSON
     }
+    if let client = state.runtimeEmailClientConfigurationsByNodeID[node.id] {
+        json["emailClient"] = [
+            "pop3Host": client.pop3Host, "pop3Port": client.pop3Port,
+            "smtpHost": client.smtpHost, "smtpPort": client.smtpPort,
+            "username": client.username, "password": client.password,
+            "name": client.name, "email": client.email,
+            "inbox": client.inbox.map(emailMessageJSON),
+            "sent": client.sent.map(emailMessageJSON),
+            "drafts": client.drafts.map(emailMessageJSON),
+            "nextMessageID": Int(client.nextMessageID),
+        ] as JSON
+    }
+    if let server = state.runtimeEmailServerConfigurationsByNodeID[node.id] {
+        json["emailServer"] = [
+            "domain": server.domain, "pop3Port": server.pop3Port,
+            "accounts": server.accounts.map { account in
+                [
+                    "username": account.username, "password": account.password, "name": account.name,
+                    "mailbox": account.mailbox.map(emailMessageJSON),
+                ] as JSON
+            },
+            "nextMessageID": Int(server.nextMessageID),
+        ] as JSON
+    }
     if let link = state.remoteLinkConfigurationsByNodeID[node.id] {
         json["remoteLink"] = [
             "pairIdentifier": link.pairIdentifier,
@@ -615,6 +639,27 @@ func foldPaths(_ cases: [PathCase]) -> [JSON] {
     }
 }
 
+func emailAddressJSON(_ address: TopologyRuntimeEmailAddress) -> [Any] {
+    [address.name ?? NSNull(), address.mailAddress]
+}
+
+func emailMessageJSON(_ message: TopologyRuntimeEmailMessage) -> JSON {
+    [
+        "id": Int(message.id),
+        "from": emailAddressJSON(message.from),
+        "to": message.to.map(emailAddressJSON),
+        "cc": message.cc.map(emailAddressJSON),
+        "bcc": message.bcc.map(emailAddressJSON),
+        "subject": message.subject,
+        "body": message.body,
+        "deliveryIdentity": message.deliveryIdentity ?? NSNull(),
+        "receivedAtMilliseconds": message.receivedAtMilliseconds.map { Int($0) } ?? NSNull(),
+        "isNew": message.isNew,
+        "isMarkedForDeletion": message.isMarkedForDeletion,
+        "isSent": message.isSent,
+    ]
+}
+
 // MARK: - /dns/hosts cases (packages/fls/test/dns-hosts.cases.txt)
 
 func dnsRecordJSON(_ record: TopologyDNSResourceRecord) -> [Any] {