feat: Add OpenAI API standardization and tooling improvements

[MnivL]

Summary

This PR introduces multiple improvements and additions to enhance code maintainability and functionality:

1. ​Gitignore Update: Added .idea/ directory to exclude IDE-specific files
2. ​API Standardization: Unified environment variables to OpenAI API format
3. ​Documentation: Added freshguide.md with:
   • Parameter configuration guidelines
   • Supported OpenAI API model provider interfaces
   • API documentation standards
4. ​Tooling Improvements:
   • Added tools() method to ANPTool (replacing get_available_tools)
   • Improved code readability and maintainability
5. ​JSON Parsing Utility:
   • Added anp_examples/utils/json_utils.py
   • Implemented robust_json_parse() function for handling function call arguments

Changes Breakdown

Core Improvements

• Git hygiene: Added .idea/ to .gitignore
• Environment standardization: Aligned env vars with OpenAI API spec
• Added comprehensive freshguide.md documentation

Code Enhancements

• Refactored tool discovery in ANPTool:
  • New tools() method (deprecates get_available_tools)
  • Improved method naming and code organization
• Added robust JSON parsing utility:
  • Handles edge cases in function call arguments
  • Properly escapes special characters
  • Supports nested JSON structures
  • Includes type safety checks

New Utility Features

The json string used to handle the arguments returned by the function call.

def robust_json_parse(raw_args: str) -> Any:
    """Handles:
    - Standard JSON
    - Quote-wrapped strings
    - Missing braces/quotes
    - Partial JSON fragments
    - Type-safe fallback
    """