75.2 IMAP: новый сервер на Reactor Netty (STARTTLS, 993, IDLE, UIDPLUS, MOVE)

Старый IMAP (выключен, .block() на сетевом потоке) удалён, написан заново:
- ImapServer: декодер целых команд с литералами ({n} после "+ Ready", {n+}),
  команды по одной на рабочем потоке; STARTTLS (без выполнения открытого текста
  после него) и неявный TLS; IDLE с опросом раз в 5 с до DONE
- ImapSession: IMAP4rev1 + LITERAL+, SASL-IR, IDLE, UIDPLUS, MOVE, UNSELECT,
  NAMESPACE, SPECIAL-USE, ID; FETCH (ENVELOPE, BODYSTRUCTURE, BODY[section]<partial>),
  SEARCH, STORE, COPY/MOVE с COPYUID, APPEND с APPENDUID, EXPUNGE/UID EXPUNGE
- MimeTree: части письма по байтам — размеры BODYSTRUCTURE совпадают с BODY[]
- V4: UID на папку выдаёт триггер (перенос из веба тоже получает новый UID),
  флаги \Answered/\Deleted, message_sources — письмо как пришло (SMTP, APPEND)
  или собранное один раз (MimeSource); правка черновика сбрасывает его
- тесты: настоящий клиент Angus IMAP, сырые литералы/IDLE/подмешивание (47 всего)
- живая проверка: обновление V3 -> V4 на PostgreSQL с письмами, Python imaplib:
  STARTTLS, 993, папки, вложения, поиск, APPEND/COPY/MOVE/EXPUNGE, IDLE — 0 ошибок

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

backend/src/main/java/com/mailserver/service/LocalDelivery.java

@@ -38,9 +38,12 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
     private final SpfService spfService;
     private final DmarcService dmarcService;
     private final String hostname;
+    private final MessageSources sources;
 
     public LocalDelivery(MailService mailService, DkimService dkimService, SpfService spfService,
-                         DmarcService dmarcService, @Value("${mailserver.smtp.hostname:localhost}") String hostname) {
+                         DmarcService dmarcService, @Value("${mailserver.smtp.hostname:localhost}") String hostname,
+                         MessageSources sources) {
+        this.sources = sources;
         this.mailService = mailService;
         this.dkimService = dkimService;
         this.spfService = spfService;
@@ -82,11 +85,13 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
             for (FilePart file : attachments(mime)) {
                 mailService.storeIncomingAttachment(stored.getId(), file.name(), file.contentType(), file.bytes());
             }
+            // IMAP serves the message exactly as it arrived
+            sources.put(stored.getId(), raw).block();
         }
     }
 
     /** "a@x, b@y" from a header, or null. A broken header is ignored, not a reason to lose the message. */
-    static String addresses(MimeMessage mime, jakarta.mail.Message.RecipientType type) {
+    public static String addresses(MimeMessage mime, jakarta.mail.Message.RecipientType type) {
         try {
             jakarta.mail.Address[] list = mime.getRecipients(type);
             if (list == null || list.length == 0) {
@@ -103,11 +108,11 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
         }
     }
 
-    record FilePart(String name, String contentType, byte[] bytes) {
+    public record FilePart(String name, String contentType, byte[] bytes) {
     }
 
     /** Parts with a file name (attachments and inline images), nested multiparts walked. */
-    static List<FilePart> attachments(Part part) throws MessagingException, IOException {
+    public static List<FilePart> attachments(Part part) throws MessagingException, IOException {
         List<FilePart> files = new ArrayList<>();
         collect(part, files);
         return files;
@@ -144,11 +149,11 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
         }
     }
 
-    record Body(String text, boolean html) {
+    public record Body(String text, boolean html) {
     }
 
     /** HTML part when the message has one, otherwise the plain text; nested multiparts are walked. */
-    static Body body(Part part) throws MessagingException, IOException {
+    public static Body body(Part part) throws MessagingException, IOException {
         String html = find(part, "text/html");
         if (html != null) {
             return new Body(html, true);