docs: add CHANGELOG.md

Document all releases from v0.1.0 to v2.2.0 following Keep a Changelog
format with comparison links.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: doitian

CHANGELOG.md

@@ -0,0 +1,87 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+- Deploy workflow for automatic crates.io publishing on tag push
+
+### Changed
+- Refactored code according to clippy warnings
+- Added clippy to CI pipeline
+- Moved tests into a separate file
+
+### Documentation
+- Added test vectors in spec
+
+## [2.2.0] - 2024-12-12
+
+### Added
+- `extract_public_key_from_slice` function to extract public key from bytes
+
+## [2.1.0] - 2024-11-29
+
+### Added
+- New interface to concat and split error packets
+
+## [2.0.0] - 2024-11-28
+
+### Changed
+- **Breaking:** Error parsing now returns hops index
+
+## [1.0.1] - 2024-09-29
+
+### Fixed
+- Outdated docs for error packet example
+
+### Changed
+- Enabled CI for merge group
+
+### Documentation
+- Fixed spec grammar errors
+
+## [1.0.0] - 2024-09-26
+
+### Added
+- `OnionPacket::from_bytes` to construct onion packet from bytes
+
+## [0.2.0] - 2024-09-25
+
+### Added
+- Support for returning error packets
+- Fiber Sphinx protocol specification
+
+### Documentation
+- Documented returned value of `peel`
+- Added spec on error packet
+- Linked code to the spec
+
+## [0.1.1] - 2024-09-23
+
+### Fixed
+- Crate publishing configuration
+
+## [0.1.0] - 2024-09-23
+
+### Added
+- Initial implementation of Sphinx mix network protocol
+- Onion packet creation with arbitrary packet data length
+- Onion packet peeling (decryption for next hop)
+- HMAC verification for packet integrity
+- Ephemeral key derivation for each hop
+- Hop shared secret derivation
+- Filler generation for packet construction
+
+[Unreleased]: https://github.com/cryptape/fiber-sphinx/compare/v2.2.0...HEAD
+[2.2.0]: https://github.com/cryptape/fiber-sphinx/compare/v2.1.0...v2.2.0
+[2.1.0]: https://github.com/cryptape/fiber-sphinx/compare/v2.0.0...v2.1.0
+[2.0.0]: https://github.com/cryptape/fiber-sphinx/compare/v1.0.1...v2.0.0
+[1.0.1]: https://github.com/cryptape/fiber-sphinx/compare/v1.0.0...v1.0.1
+[1.0.0]: https://github.com/cryptape/fiber-sphinx/compare/v0.2.0...v1.0.0
+[0.2.0]: https://github.com/cryptape/fiber-sphinx/compare/v0.1.1...v0.2.0
+[0.1.1]: https://github.com/cryptape/fiber-sphinx/compare/v0.1.0...v0.1.1
+[0.1.0]: https://github.com/cryptape/fiber-sphinx/releases/tag/v0.1.0