Add Rust dependency umbrella

[cjen1-msft]

Summary

• add a separate ccf-rs static-library umbrella around cose-rs
• retain cose-rs as a standalone staticlib/rlib crate
• build, link, and install libccf_rs.a through CMake

Testing

• Rust 1.90 dev and release builds with --locked
• cose_ffi_test
• CMake, Rust, copyright, ASCII, include, and diff checks

[Copilot]

Pull request overview

This PR introduces a new Rust “umbrella” static library (ccf-rs) which depends on (and packages) cose-rs, and updates the CMake build so ccfcrypto links against the new libccf_rs.a instead of directly linking libcose_rs.a. This fits into the broader codebase by keeping the Rust COSE implementation buildable via Cargo while presenting a single static library artifact to the CMake/C++ build.

Changes:

• Add new src/rust/ Cargo package (ccf-rs) that re-exports cose-rs and builds as a staticlib with a pinned toolchain.
• Update cose-rs crate-types to also emit an rlib (while retaining staticlib support).
• Replace the old CMake Rust build glue (cose_openssl.cmake) with ccf_rs.cmake, and relink ccfcrypto to the new Rust umbrella staticlib.

Custom instructions used:

• .github/copilot-instructions.md
• .github/instructions/reviewing.instructions.md

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/rust/src/lib.rs	Defines the umbrella crate’s root and re-exports cose_rs.
src/rust/rust-toolchain.toml	Pins the Rust toolchain for building ccf-rs.
src/rust/Cargo.toml	New ccf-rs package definition producing libccf_rs.a and depending on cose-rs.
src/rust/Cargo.lock	Locks dependency graph for reproducible ccf-rs builds.
src/rust/.gitignore	Ignores Cargo target/ output for the new crate.
src/cose/cose_rs/Cargo.toml	Extends cose-rs outputs to include rlib alongside staticlib.
CMakeLists.txt	Switches CMake inclusion from removed Rust module to the new ccf_rs.cmake.
cmake/crypto.cmake	Updates ccfcrypto to link against libccf_rs.a and depend on cargo-build_ccf_rs.
cmake/cose_openssl.cmake	Removed legacy CMake logic that built/installed libcose_rs.a directly.
cmake/ccf_rs.cmake	New CMake logic to build and install libccf_rs.a via Cargo.