refactor: migrate P2P network from Redis gossip to direct TCP mesh architecture

- Replaced Redis-based P2P with direct TCP connections for decentralized mesh networking
- Added handshake protocol with node_id exchange for peer authentication
- Implemented bidirectional connection management (inbound/outbound streams)
- Added peer dialing loop to continuously reconnect to initial peers
- Added ping/pong keepalive mechanism to maintain active connections
- Prevented duplicate connections through endpoint

systemd/aitbc-follower-node.service

@@ -1,29 +0,0 @@
-[Unit]
-Description=AITBC Blockchain Follower Node (Port 8007)
-After=network.target aitbc-blockchain-node.service
-Wants=aitbc-blockchain-node.service
-
-[Service]
-Type=simple
-User=root
-Group=root
-Environment=NODE_ENV=production
-Environment=NODE_ID=follower-node-8007
-Environment=PYTHONPATH=/opt/aitbc/apps/blockchain-node/src:/opt/aitbc/services
-Environment=BLOCKCHAIN_DATA_DIR=/var/lib/aitbc/data/follower
-Environment=BLOCKCHAIN_CONFIG_DIR=/etc/aitbc
-Environment=BLOCKCHAIN_LOG_DIR=/var/log/aitbc/production
-Environment=BLOCKCHAIN_PORT=8007
-Environment=BLOCKCHAIN_ROLE=follower
-Environment=BLOCKCHAIN_GENESIS_NODE=http://localhost:8006
-ExecStart=/opt/aitbc/venv/bin/python /opt/aitbc/services/blockchain_simple.py
-ExecReload=/bin/kill -HUP $MAINPID
-KillMode=mixed
-TimeoutStopSec=30
-Restart=always
-RestartSec=5
-StandardOutput=journal
-StandardError=journal
-
-[Install]
-WantedBy=multi-user.target