feat(ci): improve test failure comment formatting
- Add test categorization by type (unit/e2e/integration), platform (windows/linux), and bundler (turbopack/rspack/webpack)
- Add summary table with commit info, workflow run link, and re-run button
- Group tests by category with collapsible sections
- Add Datadog and source file links for each failing test
- Add local reproduction commands section
- Improve error output formatting (collapsed per category)
- Truncate long comments to stay within GitHub limits
