chore(api-keys-simplified): release v0.4.0

[github-actions]

🤖 New release

• api-keys-simplified: 0.3.0 -> 0.4.0 (⚠ API breaking changes)

⚠ api-keys-simplified breaking changes

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.45.0/src/lints/inherent_method_missing.ron

Failed in:
  ApiKey::hash, previously in file /tmp/.tmpCJCjUy/api-keys-simplified/src/domain.rs:260

Changelog

0.4.0 - 2025-12-20

Fixed

• expose salt used for hash (#22)

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This PR was generated with release-plz.