Support custom file-opening actions in keybindings (e.g., open settings.json)

Feature Request

Problem

The current keybindings system (~/.claude/keybindings.json) only supports a predefined set of internal actions (e.g., chat:submit, app:toggleTodos). There is no way to bind a keyboard shortcut to open a specific file, such as settings.json.

Use Case

Users frequently need to edit their settings.json or settings.local.json. Having a keyboard shortcut (e.g., ctrl+shift+s) to quickly open these files in an external editor would improve workflow efficiency.

Proposed Solution

Add a new keybinding action type that supports opening arbitrary files, for example:

{
  "context": "Global",
  "bindings": {
    "ctrl+shift+s": {
      "action": "app:openFile",
      "file": "~/.claude/settings.json"
    }
  }
}

Alternatively, support running shell commands via keybindings:

{
  "context": "Global",
  "bindings": {
    "ctrl+shift+s": {
      "action": "app:runCommand",
      "command": "code ~/.claude/settings.json"
    }
  }
}

Environment

• Claude Code CLI on Windows 10