Replace scanner's BatchPublisher with a pair of DB channels

processor/scanner/src/substrate/mod.rs

@@ -6,7 +6,7 @@ use serai_coins_primitives::{OutInstruction, OutInstructionWithBalance};
 
 use primitives::task::ContinuallyRan;
 use crate::{
-  db::{ScannerGlobalDb, SubstrateToEventualityDb},
+  db::{ScannerGlobalDb, SubstrateToEventualityDb, AcknowledgedBatch},
   report, ScannerFeed, KeyFor,
 };
 
@@ -79,6 +79,12 @@ impl<D: Db, S: ScannerFeed> ContinuallyRan for SubstrateTask<D, S> {
             return Ok(made_progress);
           };
 
+          {
+            let external_key_for_session_to_sign_batch =
+              report::take_external_key_for_session_to_sign_batch::<S>(&mut txn, batch_id).unwrap();
+            AcknowledgedBatch::send(&mut txn, &external_key_for_session_to_sign_batch, batch_id);
+          }
+
           // Mark we made progress and handle this
           made_progress = true;