feat(code_review): Improve debuggability

[armenzg]

This is a follow-up to #106567 which fixes the issue we found in SENTRY-5H53.

Description

This PR adds the extract_github_info() function to extract GitHub metadata from webhook events for improved debugging and logging.

In the future, we should also add this ability to Seer's code review code path.

Changes

New Function: extract_github_info()

• Extracts GitHub metadata from webhook event payloads
• Returns a dictionary with:
  • github_owner: Repository owner/organization name
  • github_repo_name: Repository name
  • github_repo_full_name: Full repository name (owner/repo)
  • github_event_url: URL to the specific event (check_run, pull_request, or comment)

Integration

• Updated handle_webhook_event() in handlers.py to use extract_github_info()
• Extracted metadata is passed as extra parameter to event handlers
• Updated check_run.py, issue_comment.py, and pull_request.py to accept extra parameter

Testing

• Added comprehensive unit test suite with 14 test cases
• Tests cover all event types (pull_request, check_run, issue_comment)
• Tests verify URL precedence logic (comment > check_run > pull_request)
• Tests use real GitHub webhook fixtures for better accuracy
• Edge cases tested (missing data, empty events, etc.)

Fixtures

• Updated GitHub fixtures to include complete repository metadata
• Added missing repository.name and repository.owner.login fields

Fixes CW-299

[linear]

CW-299 Make logging for debugging code review

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Inconsistent enum-to-string conversion for Celery task parameter

Low Severity

The process_github_webhook_event task was updated to expect github_event: str, and schedule_task now explicitly passes github_event.value with a comment about Celery serialization. However, the call in check_run.py still passes github_event (the GithubWebhookType enum) directly without converting to .value. While this works at runtime because StrEnum members are strings, it creates an inconsistency that contradicts the explicit conversion pattern established elsewhere.

Additional Locations (1)

• src/sentry/seer/code_review/webhooks/task.py#L59-L62