Fix Carrot v1 protocol TX handling for peer synchronization

Root cause: Merkle verification failures (error 659) and peer bans occurred
because protocol TX was not consistently present in m_transactions[1].

Parser fix (pool_block_parser.inl):
- Skip dummy transactions[0] entry when populating m_transactions
- Add protocol TX computation after parsing for Carrot v1 blocks

Block template fix (block_template.cpp):
- Insert protocol TX at position [1] during block creation in update()
- Insert protocol TX during select_mempool_transactions()

get_pow_hash fix (pool_block.cpp):
- Ensure protocol TX is populated before serialize_mainchain_data()

The protocol TX must be at m_transactions[1] before ANY serialization
occurs, otherwise sender and receiver compute different merkle roots.

Tested: Multiple restart cycles with two nodes, no bans, chains stay synced.

src/stratum_server.cpp

@@ -983,6 +983,19 @@ void StratumServer::on_share_found(uv_work_t* req)
 		}
 
 		hash pow_hash;
+
+                LOGINFO(0, "DEBUG stratum hash: height=" << height << " seed=" << seed_hash << " blob_size=" << blob_size);
+
+                {
+                    std::string hex;
+                    for (size_t i = 0; i < blob_size; ++i) {
+                        char buf[4];
+                        snprintf(buf, sizeof(buf), "%02x", blob[i]);
+                        hex += buf;
+                    }
+                    LOGINFO(0, "DEBUG stratum blob: " << hex);
+                }
+
 		if (!pool->calculate_hash(blob, blob_size, height, seed_hash, pow_hash, false)) {
 			LOGWARN(3, "client " << static_cast<char*>(share->m_clientAddrString) << " couldn't check share PoW");
 			share->m_result = SubmittedShare::Result::COULDNT_CHECK_POW;