Implement CLI app for API interaction with MFA

- Create full CLI application with authentication, sync triggering, and status checking
- Implement MFA support for secure authentication
- Add token management with secure local storage
- Create API client for backend communication
- Implement data models for User Session, Sync Job, and Authentication Token
- Add command-line interface with auth and sync commands
- Include unit and integration tests
- Follow project constitution standards for Python 3.13, type hints, and code quality
- Support multiple output formats (table, JSON, CSV)

cli/src/utils/config.py

@@ -0,0 +1,55 @@
+import os
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+import yaml
+
+
+class ConfigManager:
+    """Configuration management utilities for YAML config"""
+
+    def __init__(self, config_path: Optional[Path] = None):
+        if config_path is None:
+            # Use default location in user's home directory
+            self.config_path = Path.home() / ".garmin-sync" / "config.yaml"
+            self.config_path.parent.mkdir(exist_ok=True)
+        else:
+            self.config_path = config_path
+            self.config_path.parent.mkdir(parents=True, exist_ok=True)
+
+        self.config = self._load_config()
+
+    def _load_config(self) -> Dict[str, Any]:
+        """Load configuration from YAML file"""
+        if self.config_path.exists():
+            with open(self.config_path, "r") as f:
+                return yaml.safe_load(f) or {}
+        else:
+            # Return default configuration
+            default_config = {
+                "api_base_url": "https://api.garmin.com",
+                "default_timeout": 30,
+                "output_format": "table",  # Options: table, json, csv
+                "remember_login": True,
+            }
+            self._save_config(default_config)
+            return default_config
+
+    def _save_config(self, config: Dict[str, Any]) -> None:
+        """Save configuration to YAML file"""
+        with open(self.config_path, "w") as f:
+            yaml.dump(config, f)
+
+    def get(self, key: str, default: Any = None) -> Any:
+        """Get a configuration value"""
+        return self.config.get(key, default)
+
+    def set(self, key: str, value: Any) -> None:
+        """Set a configuration value"""
+        self.config[key] = value
+        self._save_config(self.config)
+
+    def update(self, updates: Dict[str, Any]) -> None:
+        """Update multiple configuration values"""
+        self.config.update(updates)
+        self._save_config(self.config)