[FEATURE] Separate diff engine fol claude code change proposal

## Feature Description

Hello! I was wondering would it be possible to delegate visual side of claude code diffs proposal to more focused plugins, like https://github.com/esmuellert/codediff.nvim or `diffview.nvim` ?

## Use Case

They do better job of showing differences than a built-in implementation, and visually much more pleasant to work with

Start by reviewing the built-in diff proposal implementation and the integration points for codediff.nvim or diffview.nvim; the issue names no project files or tests. Done means allowing the visual diff to be delegated to a focused plugin while preserving the Claude Code change-proposal workflow.

Scritto dal modello di indicizzazione a partire dal testo della issue.