Rename undirected option to add reverse edges

[adsharma]

Summary

• Rename the public undirected option to add_reverse_edges / --add-reverse-edges.
• Preserve directed input by default while allowing explicit reverse-edge expansion.
• Update docs and tests for CLI, GraphAr conversion, and the in-memory API.

Why

Some input relationships are naturally directed, for example:

user - [:livesin] -> city

That input may be directed, but callers may still want to add reverse edges for algorithms that expect symmetric adjacency, such as community detection, or for databases that prefer this denormalization to answer reverse queries efficiently.

The new name describes the actual behavior: the converter keeps the graph directed by default and only adds reverse edges when explicitly requested.

Validation

• uv run pytest tests/test_cli.py tests/test_memory.py -q

[Copilot]

Pull request overview

This PR renames the “undirected” option to an explicit reverse-edge expansion option (add_reverse_edges / --add-reverse-edges), keeping graphs directed by default while allowing symmetric adjacency when requested, and updates documentation + tests accordingly.

Changes:

• Rename the public API/CLI flag from undirected to add_reverse_edges / --add-reverse-edges.
• Update CSR conversion logic and validations to treat reverse-edge expansion as an explicit opt-in.
• Update docs/spec and tests, including a new parquet metadata assertion for icebug_disk_version.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/test_memory.py	Updates in-memory API tests to use add_reverse_edges.
tests/test_cli.py	Updates CLI conversion tests for new flag; adds parquet metadata assertion.
README.md	Updates examples and narrative to describe reverse-edge expansion instead of “undirected”.
icebug_format/memory.py	Renames parameter and updates docs/error messaging for reverse-edge expansion.
icebug_format/graphar.py	Renames flag and adds reverse-edge expansion + homogeneous-type validation.
icebug_format/cli.py	Renames CLI flag and internal parameter; updates help text and messages.
doc/spec.md	Updates CLI/spec wording from directed/undirected to direction + reverse edges.

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[aheev]

there's another problem with providing undirected / rev-edges, direction might not be same across the rel tables. Worth adding it as a caveat

[aheev]

nit: #9 (comment)