[VS Code] Copy-paste between windows doubles line breaks

Description

When copying text from one VS Code window and pasting it into Claude Code running in another VS Code window, all line breaks are doubled (single \n becomes \n\n).

Steps to Reproduce

1. Open two VS Code windows
2. In window 1: select and copy some multi-line text (code, markdown, etc.)
3. In window 2: have Claude Code running in the integrated terminal
4. Paste the text with Ctrl+V
5. Observe that every line break is now doubled

Expected Behavior

Line breaks should be preserved as-is. Single line breaks should remain single.

Actual Behavior

Original:
line 1
line 2
line 3

After paste:
line 1

line 2

line 3

Environment

• Claude Code version: 2.1.x
• VS Code version: 1.96.x
• Platform: Windows 11 + WSL2
• Terminal: VS Code integrated terminal

Impact

Medium - Makes pasting code snippets or structured text annoying, requiring manual cleanup of extra blank lines. Especially problematic when pasting code blocks or configuration files.

Notes

This may be related to how VS Code handles clipboard across windows, or how Claude Code's terminal input processes line endings (CR+LF vs LF).