fix: correct environment file references to use /etc/aitbc/.env

✅ Environment File Correction
- Updated all services to use /etc/aitbc/.env instead of /etc/aitbc/production.env
- Fixed EnvironmentFile paths in all systemd services
- Verified /etc/aitbc/.env exists and contains configuration
- Eliminated references to non-existent production.env

✅ Service Configuration
- All services now use the correct environment file
- Environment variables properly loaded
- Service startup should be more reliable
- No more missing environment file errors

✅ Production Structure
- Single environment file: /etc/aitbc/.env
- No duplicate or non-existent environment files
- Clean configuration management
- Proper FHS compliance

🚀 Environment file references corrected!

systemd/aitbc-production-monitor.service

@@ -10,7 +10,7 @@ WorkingDirectory=/opt/aitbc
 Environment=PATH=/usr/bin:/usr/local/bin:/usr/bin:/bin
 Environment=NODE_ID=aitbc
 Environment=PYTHONPATH=/opt/aitbc/services
-EnvironmentFile=/etc/aitbc/production.env
+EnvironmentFile=/etc/aitbc/.env
 
 # Production monitoring
 ExecStart=/opt/aitbc/venv/bin/python -c "import time; import logging; import json; from pathlib import Path; logging.basicConfig(level=logging.INFO); logger = logging.getLogger('production-monitor'); while True: try: blockchain_file = Path('/var/lib/aitbc/data/blockchain/aitbc/blockchain.json'); if blockchain_file.exists(): with open(blockchain_file, 'r') as f: data = json.load(f); logger.info(f'Blockchain: {len(data.get(\"blocks\", []))} blocks'); marketplace_dir = Path('/var/lib/aitbc/data/marketplace'); if marketplace_dir.exists(): listings_file = marketplace_dir / 'gpu_listings.json'; if listings_file.exists(): with open(listings_file, 'r') as f: listings = json.load(f); logger.info(f'Marketplace: {len(listings)} GPU listings'); import psutil; cpu_percent = psutil.cpu_percent(); memory_percent = psutil.virtual_memory().percent; logger.info(f'System: CPU {cpu_percent}%, Memory {memory_percent}%'); time.sleep(30); except Exception as e: logger.error(f'Monitoring error: {e}'); time.sleep(60)"