Support annotating plans with feedback for iteration

[jerop]

In #17721, we added support for editing files in preferred editor. At this time, the agent assumes the plan is final and presents it for approval.

We should expand functionality for agent to review the file first before presenting it for approval. This would allow users to annotate plans with inline feedback for faster iteration than one comment at a time.

https://boristane.com/blog/how-i-use-claude-code/#the-annotation-cycle --> example use case of annotating plans.