Function crate_edge_schema 

pub fn crate_edge_schema() -> Arc<Schema> 

Arrow schema for crate dependency edges.

Columns:

• source: the crate that declares the dependency
• target: the crate being depended upon
• version_req: semver requirement, e.g. "55", ">=1, <2", "*" for path deps
• optional: true if the dep is optional = true
• dev_dep: true if the dep came from [dev-dependencies]
• build_dep: true if the dep came from [build-dependencies]
• source_kind: provenance string — one of "workspace", "crates_io", "git", "path"