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/aitbc_cli/config/__init__.py

@@ -0,0 +1,68 @@
+"""Configuration management for AITBC CLI"""
+
+import os
+import yaml
+from pathlib import Path
+from typing import Optional
+from dataclasses import dataclass, field
+from dotenv import load_dotenv
+
+
+@dataclass
+class Config:
+    """Configuration object for AITBC CLI"""
+    coordinator_url: str = "http://127.0.0.1:18000"
+    api_key: Optional[str] = None
+    config_dir: Path = field(default_factory=lambda: Path.home() / ".aitbc")
+    config_file: Optional[str] = None
+    
+    def __post_init__(self):
+        """Initialize configuration"""
+        # Load environment variables
+        load_dotenv()
+        
+        # Set default config file if not specified
+        if not self.config_file:
+            self.config_file = str(self.config_dir / "config.yaml")
+        
+        # Load config from file if it exists
+        self.load_from_file()
+        
+        # Override with environment variables
+        if os.getenv("AITBC_URL"):
+            self.coordinator_url = os.getenv("AITBC_URL")
+        if os.getenv("AITBC_API_KEY"):
+            self.api_key = os.getenv("AITBC_API_KEY")
+    
+    def load_from_file(self):
+        """Load configuration from YAML file"""
+        if self.config_file and Path(self.config_file).exists():
+            try:
+                with open(self.config_file, 'r') as f:
+                    data = yaml.safe_load(f) or {}
+                    
+                self.coordinator_url = data.get('coordinator_url', self.coordinator_url)
+                self.api_key = data.get('api_key', self.api_key)
+            except Exception as e:
+                print(f"Warning: Could not load config file: {e}")
+    
+    def save_to_file(self):
+        """Save configuration to YAML file"""
+        if not self.config_file:
+            return
+            
+        # Ensure config directory exists
+        Path(self.config_file).parent.mkdir(parents=True, exist_ok=True)
+        
+        data = {
+            'coordinator_url': self.coordinator_url,
+            'api_key': self.api_key
+        }
+        
+        with open(self.config_file, 'w') as f:
+            yaml.dump(data, f, default_flow_style=False)
+
+
+def get_config(config_file: Optional[str] = None) -> Config:
+    """Get configuration instance"""
+    return Config(config_file=config_file)