Creating a Review document with save to project option

### Describe the feature or problem you'd like to solve

Similar to the /research (-> 'report') and /plan (-> 'plan') slash commands executing /review should also generate a standard output document.

### Proposed solution

Would provide a harmonized behavior for all three agents and a useful output for the /review command.

### Example prompts or workflows

```/review the spec @my_spec``` should result in an output document e.g. named "Review.md".
Similar for review code snippets or (implementation) plans.

### Additional context

_No response_