--checkpointing command-line flag was removed in version > 0.11.0.

[gastonmorixe]

## Enabling the Feature

The Checkpointing feature is disabled by default. To enable it, you need to edit
your `settings.json` file.

> **Note:** The `--checkpointing` command-line flag was removed in version
> 0.11.0. Checkpointing can now only be enabled through the `settings.json`
> configuration file.

Add the following key to your `settings.json`:

{
  "general": {
    "checkpointing": {
      "enabled": true
    }
  }
}

https://github.com/google-gemini/gemini-cli/blob/7a4280a482026f2127d4b9215f2cef4b58447af5/docs/cli/checkpointing.md?plain=1#L38-L57