Quick fixes from the first boot: recovery admin, upsell, warnings

- The recovery administrator (INBUXA_RECOVERY_ADMIN, or STALWART_RECOVERY_ADMIN)
  is honored only in bootstrap and recovery mode. On a configured server it's
  ignored with a startup warning. Before, it was a standing full-admin login
  for as long as the variable stayed set.
- The Enterprise upsell error is replaced by "This feature isn't available in
  INBUXA yet" for the features still to be rebuilt.
- Workspace warnings: 25 to 0. cargo fix removed the unused imports. The
  seven places where Enterprise code used to plug in keep their parameters,
  each with an inbuxa: comment naming the rebuild that uses it again. The
  antispam test's mock-server imports are back behind pending-rebuild.

crates/jmap/src/registry/mapping/queued_message.rs

@@ -22,7 +22,7 @@ use registry::{
     jmap::{IntoValue, JsonPointerPatch, RegistryJsonPatch},
     schema::{
         enums::{DeliveryErrorType, MessageFlag, RecipientFlag},
-        prelude::{ObjectType, Property},
+        prelude::Property,
         structs::{
             DeliveryError, QueueExpiry, QueueExpiryAttempts, QueueExpiryTtl, QueuedMessage,
             QueuedRecipient, RecipientStatus, ServerResponse,
@@ -40,7 +40,7 @@ use std::str::FromStr;
 use store::{
     Deserialize, IterateParams, U64_LEN, ValueKey,
     ahash::AHashSet,
-    registry::{RegistryFilterOp, RegistryQuery},
+    registry::RegistryFilterOp,
     write::{AlignedBytes, Archive, QueueClass, ValueClass, key::DeserializeBigEndian, now},
 };
 use trc::AddContext;