Recursive views over the intra-module call graph.

Two ops, both read-only:

• ls_deps/2 — DFS tree rooted at a {name, arity} definition. Each node is visited at most once across the whole tree: re-encounters (cycles or diamond joins) are marked repeat: true and not re-expanded. JSON output preserves the same shape so the full graph can be reconstructed by callers if needed.

• ls_extract/2 — the intra-module-exclusive closure: the target plus every defp reachable from the closure whose every caller (within the same module) is already in the closure. Suggestion only — used to scope what extract! would later cut.

Public defs are never pulled into the closure: we can't see their callers outside this file, so we conservatively leave them put. Both ops dispatch per module that contains the definition, so a name+arity that exists in two sibling modules surfaces twice.