support writing the review to other output locations

[andrew8088]

We want to be able to write the clod code review to multiple locations, not just commenting on a pull request, but also commenting directly on a commit or even just writing the review to stdout.

Claude Code's summary after writing the code:

New Features Added:

1. Action Inputs (action.yml):

• output_mode: Comma-separated list supporting pr_comment, commit_comment, stdout
• commit_sha: Optional specific commit SHA for commit comments

2. Strategy Pattern Architecture:

• OutputStrategy interface for consistent implementation
• PrCommentStrategy: Existing PR/issue comment logic (refactored)
• CommitCommentStrategy: Creates comments on specific commits
• StdoutStrategy: Outputs to workflow logs in plain text format

3. OutputManager Class:

• Parses and validates output mode configurations
• Handles multiple output strategies simultaneously
• Provides error resilience (continues if some strategies fail)
• Maintains backward compatibility

4. Updated Entry Points:

• prepare.ts: Uses OutputManager for initial tracking
• update-comment-link.ts: Uses OutputManager for final results

Key Features:

✅ Backward Compatibility: Default output_mode: "pr_comment" preserves existing behavior

✅ Flexible Configuration:

• output_mode: "pr_comment" - Traditional PR comments (default)
• output_mode: "commit_comment" - Comments on specific commits
• output_mode: "stdout" - Plain text output to workflow logs
• output_mode: "pr_comment,stdout" - Multiple outputs simultaneously

✅ Smart Commit Resolution:

1. Uses explicit commit_sha if provided
2. Falls back to PR HEAD commit
3. Falls back to workflow commit SHA

✅ Error Handling: Individual strategy failures don't break the entire action

✅ Context Validation: Ensures output modes are valid for the GitHub context

The implementation successfully makes the GitHub Action's review output more general and configurable while maintaining full backward
compatibility.