[Cursor] Add environment configuration guidelines and tools

[blopit]

[Cursor] Add environment configuration guidelines and tools

Overview

This PR adds comprehensive environment configuration management to the project, including guidelines, tools, and example files.

Changes

• Created environment-configuration.mdc rule file with best practices for managing environment configurations
• Implemented env_manager.py tool for environment switching, validation, and backup management
• Added example environment files for development, test, and production contexts
• Created detailed documentation for environment management in docs/environment-management.md
• Updated .gitignore to exclude environment files while keeping example files

Benefits

• Standardized approach to environment configuration across different contexts
• Improved security through proper environment isolation and validation
• Simplified environment switching with automated backup and validation
• Clear documentation for developers on environment management best practices