Add the MIT No Attribution license text and mark the crate with the
matching SPDX identifier. This makes the repository license explicit in
both the source header and Cargo package metadata, so downstream tools
can recognize the crate as MIT-0 without guessing from prose.
The license file uses the SPDX MIT-0 text with this project's copyright
holder. The Rust source keeps the machine-readable SPDX-License-Identifier
header at the top of the crate root.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
Trailer:
- SPDX-License-Identifier: MIT-0
- SPDX Specification: https://spdx.github.io/spdx-spec/v3.0.1/
- SPDX MIT-0: https://spdx.org/licenses/MIT-0.html
