Defines the Nodelike trait and Node enum that form the core abstraction for mapping semi-structured data (JSON, TOML, YAML) to a filesystem-like representation. The trait specifies methods for converting between strings, bytes, list directories, named directories, and serialized output. The Node enum (String, Bytes, List, Map) is the universal intermediate representation. This module is highly reusable: it can be extracted and adapted to support additional data formats or to build other tools that need to navigate hierarchical data via a filesystem metaphor. The pattern demonstrates clean separation of concerns and interface design.

Implements the pack command that recursively walks a filesystem directory tree and reconstructs a semi-structured data file. Contains robust symlink handling including chain detection (preventing infinite loops), escape detection (preventing symlinks that point outside the root), and inheritance of xattrs from symlink targets. The algorithm is self-contained and could be reused for any tool that needs to serialize a directory structure into a hierarchical format, with careful security checks for symlinks.

Provides a shared Config struct used across all binaries (ffs, pack, unpack) with CLI argument parsing, input/output handling, name normalization, munge policies, and error status codes. The config is parameterized by the format type and includes methods for creating readers/writers, validating names, and filtering ignored files. This pattern demonstrates how to centralize configuration for a multi-binary workspace, reducing duplication and ensuring consistent behavior. Could be extracted as a template for CLI toolchains.