feat(webhooks): parse out commenter relevant fields when receiving a github webhook

[knechtionscoding]

…webhook

What type of PR is this?

/kind feature

What this PR does / why we need it:

Extracts comment-specific fields (CommentAuthor, CommentBody, CommentURL) from GitHub webhook payloads for issue_comment, pull_request_review, and pull_request_review_comment events and exposes them as template variables for TaskSpawner prompt templates.

Previously, these fields were never parsed or included in the template variables map, causing prompt template execution to fail with map has no entry for key "CommentAuthor" when a spawner referenced {{.CommentAuthor}}.

Which issue(s) this PR is related to:

N/A

Special notes for your reviewer:

The Sender field (which was already populated) represents the user who triggered the webhook event, which is typically the same as the comment author. However, CommentAuthor is explicitly extracted from the comment/review object for clarity, and CommentBody/CommentURL provide access to the comment content rather than the parent issue/PR body.

Does this PR introduce a user-facing change?

Add CommentAuthor, CommentBody, and CommentURL template variables for GitHub comment webhook events (issue_comment, pull_request_review, pull_request_review_comment).

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Summary by cubic

Expose comment-specific template variables from GitHub webhooks so TaskSpawner prompts can use CommentAuthor, CommentBody, and CommentURL without missing-key errors. Supports issue_comment, pull_request_review, and pull_request_review_comment events.

• New Features
  • Parse commenter, body, and URL from the three comment/review events.
  • Add CommentAuthor, CommentBody, CommentURL to event data and export via ExtractGitHubWorkItem.
  • Add tests covering extraction and absence on non-comment events.

^{Written for commit 8d2c292. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

[knechtionscoding]

@gjkim42 I think this is ready for review

[knechtionscoding]

bump @gjkim42