[FEATURE] Ctrl+G editor support for AskUserQuestion

Problem Statement

Claude Code frequently generates blocks of text that require user confirmation before acting on them — commit messages, PR descriptions, file contents, configuration, etc. Currently the user can only approve as-is or describe changes in words, triggering another round-trip for Claude to re-render.

Plan mode already solves this elegantly: Claude writes a plan, the user can press Ctrl+G to open it in their editor, make direct edits, and approve. But this capability is exclusive to plan mode — it's not available during normal tool usage when Claude asks for confirmation on generated content.

Proposed Solution

This could be an extension of the AskUserQuestion tool — a new optional parameter (e.g., editableText) that presents a block of pre-filled text alongside the question. The user could then:

1. Approve the text as-is
2. Request changes by declining and providing free-text feedback (like the existing "No" + Tab flow), so Claude can revise and re-present
3. Open in editor via Ctrl+G to edit the text directly in their external editor

Claude would receive the (potentially edited) text back as part of the tool result and proceed.

Alternative Solutions

• Describing edits in words and waiting for Claude to re-render — functional but slow for small tweaks to otherwise good output
• Using the free-text "Other" option in AskUserQuestion — not practical for multi-line content
• Writing to a temp file and asking the user to edit it manually — clunky and error-prone

Use Case Example

1. User asks Claude to commit their staged changes
2. Claude generates a commit message and shows it for confirmation
3. The message is 90% right but the user wants to reword one line
4. Currently: user types "change the second bullet to say X instead of Y", Claude regenerates, user confirms — multiple round-trips
5. With this feature: user presses Ctrl+G, edits the line directly in their editor, approves — done

Other examples where this would help: editing PR descriptions before gh pr create, reviewing generated config files, tweaking file contents before Claude writes them.