feat(mail): map standard IMAP folders per profile

src/govoplan_mail/backend/config.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 from govoplan_core.mail.config import (
     ImapConfig,
+    ImapFolderMappings,
     ImapServerConfig,
     SmtpConfig,
     SmtpServerConfig,
@@ -13,6 +14,7 @@ from govoplan_core.mail.config import (
 
 __all__ = [
     "ImapConfig",
+    "ImapFolderMappings",
     "ImapServerConfig",
     "SmtpConfig",
     "SmtpServerConfig",