Updated blockchain CLI handlers to use real blockchain RPC endpoints instead of mock data:
- handle_blockchain_block(): Query /blocks/{number} endpoint instead of printing mock data
- handle_blockchain_init(): Check blockchain status via /blocks/0 instead of /rpc/init
- handle_blockchain_genesis(): Use /blocks/0 endpoint for genesis block operations
- Pass default_rpc_url to handle_blockchain_block() in unified_cli.py
Updated training