Implement automated summary generation for pull requests.

[homie-dev-mike[bot]]

• Added new functionality to generate a summary for pull requests using OpenAI.
• Created src/lib/ai/generate-pr-summary.ts to handle summary generation.
• Updated GitHub handler src/lib/github/write-code-for-github.ts to include summary comments in pull requests.
• Updated GitLab handler src/lib/github/write-code-for-gitlab.ts to include summary comments in merge requests.
• Introduced src/lib/webhooks/handle-pr-opened.ts to handle summary generation for all incoming PRs or MRs.
• Implemented the handlePROpened function for GitHub and GitLab webhook events to add the summary comments.
• Installed OpenAI package with npm install openai.
• Successfully committed changes under commit de40576.
• The changes were successful in enabling automated summary generation as planned.