[Bug] Rust type_use misses &Foo, Box<Foo> and std::io::Error, though the extractor already handles them

Summary

queries/rust.scm feeds only a bare type_identifier into @param.type, with one narrow special case for &dyn Trait. A parameter or return type written &Foo, Box<Foo> or std::io::Error produces no type_use edge.

packages/core/src/repowise/core/ingestion/queries/rust.scm:329-373

The head extractor already handles all three.

Mechanism

_rust_head_type_identifier (packages/core/src/repowise/core/ingestion/parser_helpers.py:1341-1403) unwraps reference_type/pointer_type, generic_type, scoped_type_identifier (taking the rightmost segment), and dynamic_type/abstract_type. It is registered in TYPE_HEAD_EXTRACTORS["rust"] and unit-tested on exactly these shapes in tests/unit/ingestion/test_rust_type_use.py (test_reference_and_mut_are_unwrapped, test_scoped_type_takes_rightmost_component, test_generic_head_is_the_constructor).

So the machinery exists and is proven. Only the query is narrow, which makes this a query-only change.

Repro

fn takes(x: &MyType) {}
fn boxed(y: Box<MyType>) {}
fn io() -> std::io::Error { unimplemented!() }

None of the three produces a type_use edge to MyType/Error.

Impact

Under-reporting on a common Rust shape: a borrowed or boxed parameter is the normal way to pass a type. type_use is in REACHABILITY_USE_EDGE_TYPES, so a type used only this way can read as unreachable.

Unsized. The affected shapes are not counted today.

Done looks like

The @param.type positions accept the wrapper shapes the extractor already unwraps, rather than only a bare type_identifier.

This cannot mint a wrong edge: the extractor returns the head type or nothing, and a type name that resolves to no repository symbol is dropped. The change is additive by construction.

Worth checking in the same pass whether the return-type position at :357-359 needs the same widening; it is bare-only today for the same reason.

Tests: extend tests/unit/ingestion/test_rust_type_use.py from the extractor level to the query level, asserting &Foo, Box<Foo> and std::io::Error in parameter and return position each produce a type_use edge.