Update cosmiconfig implementation

We need to update the cosmiconfig implementation to ensure it properly loads configuration from mycoder.config.js files.

Changes needed:

• Add support for ESM config files (.mjs extension)
• Enhance the getConfigFilePath function to support all config file formats
• Add a function to get all possible config file paths
• Improve loadConfig to accept a custom search path
• Add debug logging for configuration loading
• Add comprehensive tests for the cosmiconfig implementation

Benefits:

• Better support for different configuration file formats
• More flexibility in configuration loading
• Improved debugging capabilities
• Better test coverage