Implement File Reference in Assertions

[kdunee]

Why:

• Currently, IntentGuard only supports Python code objects (methods, classes, etc.) as the target of assertions.
• Users need a way to apply assertions to entire files, especially for broader code quality checks or when analyzing non-Python files.
• This feature will make IntentGuard more versatile and applicable to a wider range of use cases.

What:

• Extend the assert_code function to accept a file path as an argument.
• Modify the prompt engineering logic to handle file-level analysis, considering different file types (e.g., Python, JSON, YAML) and potentially large file sizes.
• Update documentation and examples to include file reference usage.
• Add unit tests to cover the new functionality, including tests for various file types and sizes.

Acceptance Criteria:

• Users can provide a file path to the assert_code function.
• IntentGuard can successfully analyze the provided file and apply the assertion.
• The system handles different file types (e.g., Python, JSON, YAML) appropriately.
• Documentation and examples are updated to reflect the new feature.
• Unit tests cover the file reference functionality and ensure correctness for various file types and sizes.