Implement GitHub review comment webhook handler with enhanced AI response features.

[homie-gg[bot]]

• Created a new API endpoint at src/pages/api/github/review-comment-webhook.ts to handle GitHub review comment webhooks.
• Modified src/lib/ai/chat/get-answer.ts to accommodate GitHub context by making certain fields optional.
• Added a tool getGitHubPullRequestContextTool for fetching additional GitHub pull request context when responding to comments.
• Updated the getAnswer function to support a new GitHub context by adding a new conditional check for the channel ID.
• Implemented error handling and logging for both the webhook handler and the newly created tool.
• Suggested installing @octokit/rest, though it might already be part of the project.