Code Quality: Pull Request Conversation Comments Feature to Complement Annotations

[vtsachev]

A customer is asking for a pull request comment system rather than just annotations. Here's why:

1. They want developers to explain why they aren't fixing certain issues
2. They need visibility in the conversation tab for warnings
3. They want to allow developer interaction with warnings
4. They need a way to defer fixes for issues that would pull developers out of scope
5. They want other developers to be able to reopen comments if needed
6. They use open comments as a gate to prevent merging until all comments are resolved

Background
Currently, Trunk Code Quality can create annotations on pull requests, highlighting specific issues in the code. However, a customer is requesting the ability to have these issues appear as pull request comments in the conversation tab, not just as code annotations.