[FEATURE] Auto-open and stream file edits to VS Code editor in real-time (like Kilo Code)

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

When Claude Code edits files with "Edit automatically" enabled, changes happen in the background and only appear as collapsed snippets in the chat panel. The actual file never opens in the VS Code editor unless I manually click on it.

This means I can't watch TypeScript/ESLint errors update in real-time as Claude writes code. I only see problems after the edit is complete, which breaks the feedback loop and often results in Claude completing a file with errors I could have caught mid-edit.

Proposed Solution

When Claude begins editing a file:

1. Auto-open the file in the VS Code editor (if not already open)
2. Stream changes in real-time with inline diff highlighting (red for deletions, green for additions) as Claude writes
3. Allow the editor to update live so typecheck/lint errors appear in real-time

This is how Kilo Code handles edits—you watch the file change live in the editor with red/green highlighting, and can see TypeScript errors appear as they're introduced.

Suggested Implementation

• Add a VS Code extension setting like claudeCode.openFileOnEdit: true
• When Claude starts an edit, open the file in a tab (or focus it if already open)
• Stream the diff inline as Claude writes, similar to the current diff view but live
• Keep the Problems panel updated in real-time

Current Workaround

Manually open the file before asking Claude to edit it, then watch it update. But this requires knowing which files Claude will touch in advance, which isn't always possible.

Impact

High - This would significantly improve the developer experience for anyone who wants to monitor Claude's work in real-time rather than reviewing after the fact.

Related Issues

• #11411 (always show diffs in editor)
• #1317 (manual editing of diff viewer)