The --list stdin callback was a stateless string predicate: it ignored its
opaque context and compared the input name with the fixed stdin marker. Move
that callback under its existing caller symbol into the Rust CLI archive, so
C no longer owns this policy leaf. The Rust implementation preserves the
callback ABI and returns the same 1/0 result for the marker and ordinary
names. File opening, frame parsing, diagnostics, human-readable formatting,
private file-info storage, and list orchestration remain C-owned. The optional
codec-version helpers remain untouched because their build-time library
configuration is not propagated to the Rust archive.
Test Plan:
- `clang -fsyntax-only -Iprograms -Ilib -Ilib/common -Ilib/compress -Ilib/decompress -Ilib/dictBuilder programs/fileio.c` -- passed.
- `rustfmt --edition 2021 --check --config skip_children=true rust/cli/src/lib.rs` -- passed.
- `git diff --check` and `git diff --cached --check` -- passed.
- Cargo, clippy, native builds, and upstream tests were not run per the explicit no-heavy-command constraint.