[Feature Request] Add keyboard shortcut to copy prompt input buffer to clipboard

Bug Description
Feature request: keyboard shortcut to copy the current prompt input buffer to the system clipboard

There's currently no way to copy the text I've typed into the prompt to my system clipboard without using the mouse. Mouse-selecting the input grabs the terminal's visual line wrapping (hard newlines at the wrap points), so the pasted result is full of unwanted line breaks.

The only built-in copy action (selection:copy) copies selected transcript text, and there's no bindable action for the input buffer itself.

Proposed: add a chat:copyInput action (copies the entire current input buffer to the system clipboard, preserving logical line breaks only) that can be bound in ~/.claude/keybindings.json, ideally with a sensible default (e.g. Ctrl+Y or Cmd+Shift+C while focused on the input).

Why: I frequently want to reuse or move a prompt I've drafted. Today the only clean workaround is Ctrl+G → select-all/copy in $EDITOR → quit, which is several extra steps. A direct shortcut would be a natural complement to the existing chat:externalEditor action.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.178
• Feedback ID: 970866d4-05e2-4353-bdbf-2bb12b892a72

Errors

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