[FEATURE] Generalize Plan Preview to co-edit any markdown files

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

A usual project well documented requires to do specific changes to markdown files. There is no working mode for focused markdown edits.

Proposed Solution

Claude Code Extension already knows the Plan Mode Preview Tool which allows adding comments to selected content of a markdown. Generalizing this making it available outside of Plan Mode is a low hanging fruit which would benefit everyone wanting to pin down markdown documents.

Alternative Solutions

None, perfect solution is the easiest one.

Priority

High - Significant impact on productivity

Feature Category

Tools

Use Case Example

Precisely editing markdown documentation converging towards an optimal documentation.

Additional Context

I rated priority high, because this would be a true killer feature for convergent iterative documentation editing.