Switch CI to dtolnay/rust-toolchain@nightly, run cargo directly, and fix rc5 test typo

[shekohex]

Motivation

• Modernize and simplify GitHub Actions by using dtolnay/rust-toolchain@nightly and invoking cargo directly instead of relying on the actions-rs helper actions.

Description

• Updated CI workflow /.github/workflows/ci.yml to use dtolnay/rust-toolchain@nightly and replace actions-rs/cargo@v1 steps with direct run: cargo build and run: cargo test invocations.
• Updated lints workflow /.github/workflows/lints.yml to use dtolnay/rust-toolchain@nightly, enable rustfmt and clippy components, and run cargo fmt --all -- --check and cargo clippy -- -D warnings directly.
• Fixed a typo in crates/crypto/src/rc5.rs where origional was renamed to original in an assertion inside the encrypt_decrypt test.

Testing

• Ran cargo fmt --all -- --check and cargo clippy -- -D warnings and they succeeded.
• Ran cargo build and cargo test and all unit tests (including the rc5 tests) passed.

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Codex Task