Improve transaction fee handling in BlockAssembler

- Added logging for transactions that do not meet the minimum fee requirement, providing better visibility into fee-related decisions.
- Enhanced the handling of modified transactions by erasing them from the modified transaction map and inserting them into a failed transaction set when the fee is insufficient.

These changes aim to improve debugging and transaction management within the mining process.

src/miner.cpp

@@ -473,8 +473,15 @@ void BlockAssembler::addPackageTxs(int& nPackagesSelected, int& nDescendantsUpda
 
         if (packageFees < minFee)
         {
-            // Everything else we might consider has a lower fee rate
-            return;
+            LogPrintf("tx - %s, fee - %s, minFee - %s\n", iter->GetTx().GetHash().GetHex(), packageFees, minFee);
+
+            if (fUsingModified)
+            {
+                mapModifiedTx.get<ancestor_score>().erase(modit);
+                failedTx.insert(iter);
+            }
+
+            continue;
         }
 
         CTransactionRef tx = iter->GetSharedTx();