chore: sync GovOPlaN module split state

README.md

@@ -60,6 +60,11 @@ Development mailbox routes are registered by the mail module only when the
 core runtime is in `dev` mode and `dev_mailbox_api_enabled` is enabled. Core
 does not contribute these routes directly.
 
+POP3 and JMAP are deferred. The protocol decision is documented in
+[docs/MAIL_PROTOCOL_ROADMAP.md](docs/MAIL_PROTOCOL_ROADMAP.md): stabilize
+SMTP/IMAP first, prefer JMAP for modern mailbox sync/search later, and add POP3
+only for explicit legacy-download requirements.
+
 Platform RBAC and governance rules are documented in `govoplan-core/docs/`.
 
 ## Release packaging