fix one critical bug and mostly code quality/cleanup items for portability, minor cleanup for compile on mac, fixed null check, Remove redundant TX_VERSION check

src/side_chain.cpp

@@ -958,7 +958,8 @@ bool SideChain::get_outputs_blob(PoolBlock* block, uint64_t total_reward, std::v
                                 const PoolBlock::TxOutput& output = block->m_outputAmounts[i];
                                 writeVarint(output.m_reward, blob);
                                 blob.emplace_back(TXOUT_TO_CARROT_V1);
-                                blob.insert(blob.end(), block->m_ephPublicKeys[i].h, block->m_ephPublicKeys[i].h + HASH_SIZE);
+                                const hash eph_key = block->m_ephPublicKeys[i];
+                                blob.insert(blob.end(), eph_key.h, eph_key.h + HASH_SIZE);
                                 // Carrot v1 format
                                 blob.push_back(4);
                                 blob.push_back('S');
@@ -3458,12 +3459,6 @@ bool SideChain::validate_loaded_checkpoints()
 
             PoolBlock* block = const_cast<PoolBlock*>(found);
 
-            if (!block) {
-                // Block not yet synced but reachable - can't validate yet
-                LOGWARN(3, "Checkpoint at height " << cp.height << " not yet synced, deferring validation - mining blocked");
-                return false;  // NOT safe to mine yet
-            }
-
             if (block->m_sidechainId != cp.id) {
                 LOGWARN(0, "CHECKPOINT MISMATCH at height " << cp.height <<
                         ": cached=" << cp.id <<