new feature: Use GitHub Models for weekly summary generation

### Feature Description

Suggest migrating the OpenDAL weekly summary automation script from a custom OpenAI API to GitHub Models (native AI in GitHub Actions). This will simplify secrets management, improve security, and integrate directly with GitHub Actions workflows.

### Problem and Solution

Currently, a custom OpenAI API key and configuration are required, which adds management overhead. GitHub Models now support direct AI calls in Actions for tasks like summarization and content generation. Please refer to Automate your project with [GitHub Models in Actions](https://github.blog/ai-and-ml/generative-ai/automate-your-project-with-github-models-in-actions/) for implementation ideas.

### Additional Context

- You can use ‎`gh models run` or ‎`actions/ai-inference` to generate the summary without any third-party API.
- [GitHub Models in Actions](https://github.blog/ai-and-ml/generative-ai/automate-your-project-with-github-models-in-actions/)
- [Example: Use GitHub Models with GitHub Actions to summarize issues](https://docs.github.com/en/github-models/github-models-at-scale/use-models-at-scale#example-use-github-models-with-github-actions-to-summarize-issues)

### Are you willing to contribute to the development of this feature?

- [ ] Yes, I am willing to contribute to the development of this feature.