refactor: move brother_node development artifact to dev/test-nodes subdirectory

Development Artifact Cleanup:
✅ BROTHER_NODE REORGANIZATION: Moved development test node to appropriate location
- dev/test-nodes/brother_node/: Moved from root directory for better organization
- Contains development configuration, test logs, and test chain data
- No impact on production systems - purely development/testing artifact

✅ DEVELOPMENT ARTIFACTS IDENTIFIED:
- Chain ID: aitbc-brother-chain (test/development chain)
- Ports: 8010 (P2P) and 8011 (RPC) - different from production
- Environment: .env file with test configuration
- Logs: rpc.log and node.log from development testing session (March 15, 2026)

✅ ROOT DIRECTORY CLEANUP: Removed development clutter from production directory
- brother_node/ moved to dev/test-nodes/brother_node/
- Root directory now contains only production-ready components
- Development artifacts properly organized in dev/ subdirectory

DIRECTORY STRUCTURE IMPROVEMENT:
📁 dev/test-nodes/: Development and testing node configurations
🏗️ Root Directory: Clean production structure with only essential components
🧪 Development Isolation: Test environments separated from production

BENEFITS:
✅ Clean Production Directory: No development artifacts in root
✅ Better Organization: Development nodes grouped in dev/ subdirectory
✅ Clear Separation: Production vs development environments clearly distinguished
✅ Maintainability: Easier to identify and manage development components

RESULT: Successfully moved brother_node development artifact to dev/test-nodes/ subdirectory, cleaning up the root directory while preserving development testing environment for future use.

dev/test-nodes/brother_node/.env

@@ -0,0 +1,12 @@
+CHAIN_ID=aitbc-brother-chain
+SUPPORTED_CHAINS=aitbc-brother-chain
+DB_PATH=./data/brother_chain.db
+PROPOSER_ID=aitbc-brother-proposer
+PROPOSER_KEY=0x0000000000000000000000000000000000000000000000000000000000000001
+BLOCK_TIME_SECONDS=3
+P2P_BIND_HOST=0.0.0.0
+P2P_BIND_PORT=8010
+RPC_BIND_HOST=0.0.0.0
+RPC_BIND_PORT=8011
+GOSSIP_BACKEND=memory
+MEMPOOL_BACKEND=database

dev/test-nodes/brother_node/node.log

@@ -0,0 +1,2 @@
+{"timestamp": "2026-03-15T10:11:32.915234Z", "level": "INFO", "logger": "__main__", "message": "Starting blockchain node", "supported_chains": "aitbc-brother-chain"}
+{"timestamp": "2026-03-15T10:11:32.916861Z", "level": "INFO", "logger": "aitbc_chain.consensus.poa", "message": "Starting PoA proposer loop"}

dev/test-nodes/brother_node/rpc.log

@@ -0,0 +1,18 @@
+INFO:     Started server process [977321]
+INFO:     Waiting for application startup.
+{"timestamp": "2026-03-15T10:11:08.623101Z", "level": "INFO", "logger": "aitbc_chain.app", "message": "Blockchain node started", "supported_chains": "aitbc-brother-chain"}
+INFO:     Application startup complete.
+INFO:     Uvicorn running on http://0.0.0.0:8011 (Press CTRL+C to quit)
+INFO:     127.0.0.1:39938 - "GET /health HTTP/1.1" 200 OK
+INFO:     127.0.0.1:37594 - "GET /rpc/head?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     127.0.0.1:50756 - "POST /rpc/admin/mintFaucet HTTP/1.1" 200 OK
+INFO:     127.0.0.1:44414 - "GET /rpc/getBalance/aitbc1e3bdd9ef1e8aba996a2baaa047aed9fd233f6298?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     127.0.0.1:59906 - "GET /rpc/syncStatus?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     127.0.0.1:53170 - "GET /rpc/head?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     127.0.0.1:40422 - "POST /rpc/admin/mintFaucet?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     127.0.0.1:40434 - "GET /rpc/getBalance/aitbc1e3bdd9ef1e8aba996a2baaa047aed9fd233f6298?chain_id=aitbc-brother-chain HTTP/1.1" 200 OK
+INFO:     Shutting down
+INFO:     Waiting for application shutdown.
+{"timestamp": "2026-03-15T21:49:09.055353Z", "level": "INFO", "logger": "aitbc_chain.app", "message": "Blockchain node stopped"}
+INFO:     Application shutdown complete.
+INFO:     Finished server process [977321]