```

chore: enhance .gitignore and remove obsolete documentation files

- Reorganize .gitignore with categorized sections for better maintainability
- Add comprehensive ignore patterns for Python, Node.js, databases, logs, and build artifacts
- Add project-specific ignore rules for coordinator, explorer, and deployment files
- Remove outdated documentation: BITCOIN-WALLET-SETUP.md, LOCAL_ASSETS_SUMMARY.md, README-CONTAINER-DEPLOYMENT.md, README-DOMAIN-DEPLOYMENT.md
```

systemd/aitbc-gpu-miner.service

@@ -0,0 +1,28 @@
+[Unit]
+Description=AITBC GPU Miner Client
+After=network.target
+Wants=network.target
+
+[Service]
+Type=simple
+User=debian
+Group=debian
+WorkingDirectory=/home/debian/aitbc
+Environment=PYTHONPATH=/home/debian/aitbc
+ExecStart=/home/debian/aitbc/venv/bin/python /home/debian/aitbc/gpu_miner_simple.py
+Restart=on-failure
+RestartSec=30
+StartLimitInterval=300
+StartLimitBurst=5
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=aitbc-gpu-miner
+
+# Security settings
+NoNewPrivileges=true
+PrivateTmp=true
+ProtectSystem=strict
+ReadWritePaths=/home/debian/aitbc
+
+[Install]
+WantedBy=multi-user.target