feat: move data directory from repository to system location

✅ Data Directory Restructure
- Moved /opt/aitbc/data to /var/lib/aitbc/data (proper system location)
- Updated all production services to use system data path
- Updated systemd services to use system data path
- Created symlink for backward compatibility
- Created proper data directories in /var/lib/aitbc/data/

✅ Services Updated
- Marketplace: /var/lib/aitbc/data/marketplace
- Blockchain: /var/lib/aitbc/data/blockchain
- OpenClaw: /var/lib/aitbc/data/openclaw
- All services now using system data paths

✅ System Compliance
- Data stored in /var/lib/aitbc (FHS compliant)
- Repository no longer contains runtime data
- Backward compatibility maintained with symlink
- Production services using correct system paths

🚀 AITBC now follows proper system data directory structure!

production/services/marketplace.py

@@ -54,7 +54,7 @@ class ProductionMarketplace:
     """Production-grade marketplace with persistence"""
     
     def __init__(self):
-        self.data_dir = Path('/opt/aitbc/production/data/marketplace')
+        self.data_dir = Path("/var/lib/aitbc/data/marketplace")
         self.data_dir.mkdir(parents=True, exist_ok=True)
         
         # Load existing data