refactor: Replace Hugging Face API calls with Ollama

[k-zehnder]

Description

This pull request refactors the summarization functionality to use the Ollama API instead of Hugging Face. The change is motivated by the availability of a dedicated machine capable of running Ollama, allowing for improved summary quality and performance.

Changes Made

• Replaced Hugging Face API integration with Ollama API.
• Adjusted prompt structure and response parsing for Ollama compatibility.
• Updated Zod validation schema to align with Ollama response format.

Testing

• Manually tested summarization with various articles to ensure consistent output.
• Verified response parsing and validation against actual Ollama responses.
• Updated and executed all relevant unit tests to validate integration.

Checklist

• My code follows the style guidelines and best practices of this project.
• I have reviewed and tested the code changes thoroughly.
• I have added or updated unit tests to cover the modified code and ensure its correctness.
• All existing unit tests pass with the changes.
• The changes do not introduce any known security vulnerabilities.
• I have considered the impact of these changes on performance, scalability, and maintainability.
• The documentation has been updated to reflect the changes introduced (if applicable).