feat: auto-finalize batches on Alpha testnet (#791)

Co-authored-by: maskpp <maskpp266@gmail.com>

contracts/src/L1/rollup/ScrollChain.sol

@@ -264,6 +264,13 @@ contract ScrollChain is OwnableUpgradeable, IScrollChain {
 
         emit CommitBatch(publicInputHash);
 
+        // As we are getting close to sunsetting the Alpha testnet,
+        // we now auto-finalize every batch to enable withdrawals.
+        lastFinalizedBatchHash = publicInputHash;
+        finalizedBatches[_batch.batchIndex] = publicInputHash;
+        _batchInStorage.finalized = true;
+        emit FinalizeBatch(publicInputHash);
+
         return publicInputHash;
     }