[FEATURE] Interactive TTY mode for bash commands — enable real-time stdin/keyboard input

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently, when Claude Code executes bash commands (either via the tool or the ! escape), there is no interactive TTY or stdin access. The process runs non-interactively: it executes, returns the output, and that's it. The user cannot send keystrokes to the running process.

This means any interactive terminal application is impossible to run inside Claude Code:

• vim, htop, nano — none of them work
• Games or TUI apps built with blessed, curses, ink — can't receive keyboard input
• Any Node.js script using process.stdin.setRawMode(true) — fails because there's no TTY

Claude Code itself confirms this when you try: "the Bash tool doesn't have a TTY or interactive input"

Proposed Solution

Add an interactive mode for bash execution in Claude Code where:

• The running process gets a real PTY (pseudo-terminal) with stdin connected to the user's keyboard
• The user can send keystrokes in real-time to the process
• The process output is rendered live in the terminal
• The user can exit back to Claude Code (e.g., with a hotkey like Ctrl+C or when the process ends)

This could be:

• A flag on the bash tool: interactive: true
• A dedicated slash command: /shell or /interactive
• An enhancement to the ! escape to actually pass through to the real terminal
• A new plugin capability that allows plugins to register custom Ink components with keyboard access

Use Cases

• Running TUI tools while Claude works (htop, lazygit, tig)
• Quick edits with vim/nano without leaving Claude Code
• Terminal games/entertainment while waiting for long Claude tasks (the original motivation — a dino runner game!)
• Interactive scripts that require user input (installers, setup wizards, CLI tools with prompts)
• REPL sessions (node, python, irb) for quick testing

Current Workaround

The only workaround is opening a separate terminal tab, which breaks the workflow of staying in a single window.

Additional Context

The plugin system currently supports slash commands, agents, hooks, MCP servers, and LSP servers — but no custom UI components. Adding either interactive TTY support OR the ability for plugins to inject custom Ink components into the Claude Code UI would solve this.

Related: this would complement the existing ! escape feature and make it actually useful for interactive commands.