Add AI-powered commit and PR description generation

[Cellcote]

Summary

This PR adds AI-powered generation of commit messages and pull request descriptions using GitHub Models API (Azure OpenAI). Users can now use the --ai flag with commit, ship, and pr commands to automatically generate descriptions based on git diffs.

Key Changes

• New AiService: Created AiService.cs with methods to generate commit messages and PR descriptions via GitHub Models API

  • GenerateCommitMessageAsync(): Generates conventional commit messages from diffs
  • GeneratePrDescriptionAsync(): Generates PR titles and structured descriptions with summary and changes sections
  • GetTokenAsync(): Retrieves GitHub token from environment variable or gh CLI
  • Includes JSON serialization context for OpenAI-compatible API requests
  • Implements diff truncation (8000 char limit) and response parsing

• CommitCommand: Added --ai flag to generate commit messages

  • Made message argument optional with null default
  • Prompts user to confirm AI-generated message or enter custom message
  • Falls back to interactive prompt if AI generation fails or is not requested

• ShipCommand: Added --ai flag to generate commit messages

  • Made message argument optional
  • Reuses CommitCommand.GenerateCommitMessageWithAi() for consistency

• PrCommand: Added --ai flag to generate PR title and description

  • Generates both title and body when --ai is used without explicit title
  • Passes generated body to gh pr create command
  • Shows generated content to user for confirmation before creating PR

Implementation Details

• Uses GitHub Models API endpoint with gpt-4o-mini model
• Requires GITHUB_TOKEN environment variable or authenticated gh CLI
• Implements proper error handling with user-friendly messages
• Uses Spectre.Console for interactive prompts and status spinners
• All AI calls have 30-second timeout and 500 token limit
• Temperature set to 0.3 for more deterministic outputs

https://claude.ai/code/session_01CSf8jFLPGw7CicGJpkaEiU