Refactor query_model: Replace if-elif chain with function-based dispatch

[geogod42]

Refactored the query_model function to improve its readability and maintainability. Specifically, it replaces the if-elif chain with a dictionary-based dispatch to separate model-specific handler functions.

Key Changes:

1. Introduced a model_dispatch dictionary for dynamic function calls based on model_str.
2. Added separate handler functions for each model (e.g., handle_gpt4o, handle_claude_35_sonnet, etc.).
3. Preserved all existing features and functionality.
4. Added comments and docstrings to enhance code clarity.

Note: I don't have tokens to test with every API, but the changes should work as intended.