75.4 Ловушка почты: catch-all только для адресов без своего ящика, файл с паролями

- MailRouter: существующий ящик получает свою почту, всё остальное (и чужие домены) —
  в ящик MAIL_CATCH_ALL; раньше ловушка забирала и письма между ящиками стенда
- DataInitializer: ящик-ловушка создаётся при старте; случайные пароли — в
  MAIL_PASSWORDS_FILE (права 600, в образе /app/data/initial-passwords.txt)
- docker-compose.jambotron.yml: MAIL_CATCH_ALL=trap@mail.test по умолчанию
- README: ловушка, файл паролей, что нужно для staging Jambotron (TCP-проброс SMTP)
- тесты: MailRouterTest, DataInitializerTest (33 всего)

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

backend/src/main/java/com/mailserver/config/DataInitializer.java

@@ -9,12 +9,27 @@ import org.springframework.boot.CommandLineRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.nio.file.attribute.PosixFilePermissions;
 import java.security.SecureRandom;
+import java.time.Instant;
 import java.util.Base64;
+import java.util.Locale;
 
 /**
- * First mailbox on an empty database: {@code mailserver.admin.email} (default admin@<first domain>) with
- * {@code mailserver.admin.password}; no password given — a random one, printed to the log once.
+ * Mailboxes the server needs on start:
+ * <ul>
+ *   <li>the first mailbox on an empty database — {@code mailserver.admin.email} (default admin@&lt;first domain&gt;)
+ *       with {@code mailserver.admin.password};</li>
+ *   <li>the catch-all mailbox ({@code mailserver.catch-all}) if it does not exist yet — mail to unknown addresses is
+ *       stored there, so it must exist.</li>
+ * </ul>
+ * A generated password is appended to {@code mailserver.passwords-file} (mode 600, in the data volume) — read it once
+ * and change the password. Without the file setting it is printed to the log once.
  */
 @Configuration
 public class DataInitializer {
@@ -24,23 +39,52 @@ public class DataInitializer {
     @Bean
     public CommandLineRunner initDatabase(UserService userService, UserRepository userRepository, MailDomains domains,
                                           @Value("${mailserver.admin.email:}") String email,
-                                          @Value("${mailserver.admin.password:}") String password) {
+                                          @Value("${mailserver.admin.password:}") String password,
+                                          @Value("${mailserver.passwords-file:}") String passwordsFile) {
         return args -> {
-            if (userRepository.count().block() > 0) {
-                return;
+            Path file = passwordsFile.isBlank() ? null : Path.of(passwordsFile);
+            if (userRepository.count().block() == 0) {
+                String address = email.isBlank() ? "admin@" + domains.domains().iterator().next() : email.trim().toLowerCase(Locale.ROOT);
+                create(userService, address, password, "Administrator", file);
             }
-            String address = email.isBlank() ? "admin@" + domains.domains().iterator().next() : email.trim().toLowerCase();
-            boolean generated = password.isBlank();
-            String secret = generated ? randomPassword() : password;
-            userService.register(address, secret, "Administrator").block();
-            if (generated) {
-                log.warn("First mailbox created: {} — password: {} (shown once, change it)", address, secret);
-            } else {
-                log.info("First mailbox created: {}", address);
+            String catchAll = domains.catchAll();
+            if (catchAll != null && !Boolean.TRUE.equals(userRepository.existsByEmail(catchAll).block())) {
+                create(userService, catchAll, "", "Mail trap", file);
             }
         };
     }
 
+    private static void create(UserService userService, String address, String password, String name, Path file)
+            throws IOException {
+        boolean generated = password.isBlank();
+        String secret = generated ? randomPassword() : password;
+        userService.register(address, secret, name).block();
+        if (!generated) {
+            log.info("Mailbox created: {}", address);
+        } else if (file != null) {
+            appendPassword(file, address, secret);
+            log.warn("Mailbox created: {} — password in {} (change it)", address, file);
+        } else {
+            log.warn("Mailbox created: {} — password: {} (shown once, change it)", address, secret);
+        }
+    }
+
+    static void appendPassword(Path file, String address, String password) throws IOException {
+        if (file.getParent() != null) {
+            Files.createDirectories(file.getParent());
+        }
+        if (!Files.exists(file)) {
+            Files.createFile(file);
+            try {
+                Files.setPosixFilePermissions(file, PosixFilePermissions.fromString("rw-------"));
+            } catch (UnsupportedOperationException ignored) {
+                // not a POSIX file system (Windows) — nothing to restrict
+            }
+        }
+        Files.writeString(file, Instant.now() + " " + address + " " + password + System.lineSeparator(),
+                StandardCharsets.UTF_8, StandardOpenOption.APPEND);
+    }
+
     private static String randomPassword() {
         byte[] bytes = new byte[18];
         new SecureRandom().nextBytes(bytes);