feat: add GPU-specific fields to marketplace offers and create dedicated GPU marketplace router

- Add GPU fields (model, memory, count, CUDA version, price, region) to MarketplaceOffer model
- Create new marketplace_gpu router for GPU-specific operations
- Update offer sync to populate GPU fields from miner capabilities
- Move GPU attributes from generic attributes dict to dedicated fields
- Update MarketplaceOfferView schema with GPU fields
- Expand CLI README with comprehensive documentation and

cli/test_ollama_blockchain.py

@@ -17,7 +17,7 @@ import json
 import httpx
 
 # Configuration
-DEFAULT_COORDINATOR = "http://127.0.0.1:18000"
+DEFAULT_COORDINATOR = "http://localhost:8000"
 DEFAULT_BLOCKCHAIN = "http://127.0.0.1:19000"
 DEFAULT_API_KEY = "${CLIENT_API_KEY}"
 DEFAULT_PROMPT = "What is the capital of France?"