Configurable cursor shape in the prompt input (bar/underline instead of block)

What

The prompt input renders the text cursor as a solid inverse-video block over the character at the caret position. There's currently no way to change this — Claude Code draws it directly, so the terminal's native cursor-shape setting (e.g. a thin bar in Warp/iTerm/etc.) doesn't apply inside the input.

Why

The block cursor obscures the character it sits on and feels heavy compared to a thin blinking bar. Many users set their terminal cursor to a bar/beam and expect that style to carry through; the mismatch is jarring — a DOS-era block in an otherwise modern TUI.

Request

Add an option to choose the input cursor style — at minimum bar (thin vertical line) and underline, alongside the current block. Ideally:

• a settings.json key, e.g. "cursorShape": "bar" | "underline" | "block", or
• respect the terminal's reported cursor shape (DECSCUSR) and don't override it.

Environment

• Claude Code CLI
• Terminal: Warp (macOS) with native bar cursor — block still shown inside Claude Code input