[BUG] Plan review: "Edit with Claude" revise window loses entered text when accidentally closed or when switching chats

Environment: Claude Code desktop app, Windows 11 Pro (10.0.26200)

Description:
When reviewing a plan (plan mode), the "Edit with Claude" revise window does not preserve entered text. If the window is accidentally closed or the user switches to another chat, all typed revision instructions are lost — no draft is saved and no confirmation prompt is shown. For long, detailed plan feedback this means retyping everything from scratch.

Steps to reproduce:

1. Claude presents a plan in plan mode
2. Select text in the plan → click "Edit with Claude"
3. Type revision instructions into the window
4. Accidentally close the window or switch to another chat

Expected behavior: The draft is preserved and restored when the window is reopened, or at minimum a confirmation prompt appears before discarding unsaved input.

Actual behavior: Entered text is lost silently.