chore: harden release workflow

[DCjanus]

Why

• Prevent release tags from publishing the wrong crate version.
• Keep the release workflow and release-note style easy to follow for future maintenance.

What

• Add a release workflow check that requires vX.Y.Z tags to match Cargo.toml package.version.
• Use the stable Rust toolchain action before running release checks and cargo publish.
• Document the release process, GitHub release-note command, and release-related agent guidance.

Validation

• GITHUB_REF_NAME=v0.19.0 version check passes locally.
• GITHUB_REF_NAME=v9.9.9 version check fails locally as expected.
• prek run --all-files

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.00%. Comparing base (5a61e79) to head (c8fe79e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #41   +/-   ##
=======================================
  Coverage   76.00%   76.00%           
=======================================
  Files           2        2           
  Lines          50       50           
=======================================
  Hits           38       38           
  Misses         12       12           

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[Copilot]

Pull request overview

Adds a safeguard and documentation around the crate release flow so publishing only occurs when the pushed vX.Y.Z tag matches the crate version in Cargo.toml, and so future release maintenance work has a clear reference.

Changes:

• Add a GitHub Actions step to validate GITHUB_REF_NAME (tag) matches Cargo.toml package version before authenticating to crates.io and publishing.
• Add docs/release.md describing tagging, publishing, and GitHub release notes creation.
• Add AGENTS.md guidance to consult the release process doc for release-related work.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
docs/release.md	Documents the intended release/tagging workflow and GitHub release notes process.
AGENTS.md	Points release-related tasks to the release process documentation.
.github/workflows/release.yml	Enforces tag/version matching prior to crates.io auth and cargo publish.

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