Feature: Review mode

[adnaan]

• Built like: https://github.com/livetemplate/prereview. possibility for integration for common code.
• Rendered markdown allows you to leave comments which can be fed back to llm for feedback
• tinkerdown:review skill which starts in tinkerdown serve --review and processes a new comment on clicking a hand off button
• every line or block(code, diagram, embed, image) is comment-able
• there is a button to see all comments