Support Running Without Triggering npm pack | postbuild support

# Description:

It would be helpful to allow the tool to run directly on the current folder without automatically triggering `npm pack`.

# Use Case:

I want to use this tool as part of a `postbuild` script. However, the current behavior causes an infinite loop:

- `npm postbuild` triggers `attw`
- `attw` triggers `npm pack`
- `npm pack` triggers `npm build`
- `npm build` triggers `npm postbuild`
- ...and the cycle **repeats**

# Current Workaround:

To avoid this loop, I manually create a tarball and run `attw` on it:
```
"postbuild": "tar -czf dist/archive.tgz LICENSE README.md dist/cjs dist/esm dist/umd docs package.json && npx attw --format ascii dist/archive.tgz && rm dist/archive.tgz"
```

# Proposed Solution:

Introduce an option or flag to allow `attw` to operate directly on the current directory without invoking `npm pack`.

Start by locating the attw CLI path that invokes npm pack and review how command-line options are parsed. The change is complete when attw can analyze the current directory without invoking npm pack, so it can run from a postbuild script without triggering the build loop.

Written by the indexing model from the issue text.