🔧 Database Path Standardization:
• Change DATABASE_URL environment variable to EXCHANGE_DATABASE_URL
• Update default database path from ./exchange.db to /var/lib/aitbc/data/exchange/exchange.db
• Apply consistent path resolution across all exchange database connections
• Update database.py, seed_market.py, and simple_exchange_api.py with new path
• Maintain backward compatibility through
- Change file mode from 644 to 755 for all project files
- Add chain_id parameter to get_balance RPC endpoint with default "ait-devnet"
- Rename Miner.extra_meta_data to extra_metadata for consistency