/resume silently overwrites clipboard in ctrl-alt-c instance, destroying user content

Bug Report

What happened

When /resume is run inside a Claude instance opened via ctrl-alt-c (which doesn't support session resumption), it silently falls back to copying a cd --resume <session-id> command to the clipboard — without any warning or user consent.

Why this is harmful

The clipboard is user-owned shared state. Users frequently copy content specifically to paste into Claude — conversation logs, error output, code, etc. Silently overwriting the clipboard destroys that content with no recovery path.

In this specific case, a user lost ~200 lines of conversation they had copied to share with Claude. The /resume command offered no warning before nuking their clipboard.

Expected behavior

• If /resume cannot work in the current context, it should fail clearly with an error message explaining why.
• It should never write to the clipboard without explicit user permission.
• At minimum, if clipboard-copy is the intended fallback, it should ask first: "Copy the resume command to your clipboard? (this will overwrite current clipboard contents)"

Steps to reproduce

1. Copy something important to your clipboard.
2. Open Claude via ctrl-alt-c.
3. Run /resume in that instance.
4. Observe clipboard is silently overwritten.

Platform

• Windows 11
• Claude Code (ctrl-alt-c desktop shortcut)