[BUG] VSCode extension: whitespace stripped at inline element boundaries when copying from chat panel

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

When selecting and copying text from the VSCode extension's chat panel (Ctrl+C), whitespace adjacent to inline formatting elements (bold, links, code spans) is stripped from the clipboard HTML. Pasting into any rich-text target (Slack, Notion, Google Docs) produces words jammed together at formatting boundaries.

Example: a response containing "word next" pastes into Slack as "wordnext" — the bold renders correctly but the space between the bold text and the next word is missing.

This affects <strong>, <a>, <em>, <code>, and <span> elements. Every inline formatting boundary is a potential break point.

Expected Behavior

Copied text preserves whitespace at all inline element boundaries, matching what's visually rendered in the chat panel.

How to Reproduce

1. Open Claude Code in VSCode extension
2. Get a response containing bold text adjacent to normal text (e.g. "word next")
3. Select the text, Ctrl+C
4. Paste into Slack (or Notion, Google Docs, any rich-text editor)
5. Observe: space between "word" and "next" is missing

Root Cause

The chat panel renders markdown via ReactMarkdown, which produces HTML like <strong>word</strong>next with no whitespace node between the closing tag and adjacent text. The browser's native copy serializes this to text/html faithfully, preserving the missing whitespace. There is no copy event listener on the chat container to normalize it.

Code block copy buttons use navigator.clipboard.writeText() (text/plain only), and there's no intervention on general DOM selection copy.

Confirmed Fix

A copy event listener appended to the webview that intercepts the copy event, clones the selection, and injects spaces at inline element boundaries before writing to clipboardData:

document.addEventListener('copy', function(e) {
  var sel = window.getSelection();
  if (!sel || !sel.rangeCount || sel.isCollapsed) return;
  var c = document.createElement('div');
  c.appendChild(sel.getRangeAt(0).cloneContents());
  var html = c.innerHTML;
  if (!html || !html.trim()) return;
  html = html.replace(/<\/(strong|b|a|em|i|code|span)>([^\s<.,;:!?)}\]])/g, '</$1> $2');
  html = html.replace(/([^\s>({\["])<(strong|b|a|em|i|code)([\s>])/g, '$1 <$2$3');
  e.clipboardData.setData('text/html', html);
  e.clipboardData.setData('text/plain', sel.toString());
  e.preventDefault();
});

Tested locally by patching webview/index.js. Slack paste now preserves spacing correctly.

Environment

• Claude Code: 2.1.216
• VSCode: Windows 11
• Platform: VSCode extension (not terminal CLI)

Related Issues

• #54670 - Feature request for "copy as markdown source" (different issue, but same surface)
• #72565 - TUI strips rich clipboard flavors (same family, different code path)
• #61021 - Selection/copy difficulties in VSCode