Release v0.3.1 (#27)

* docs: Add CLAUDE.md with project guidelines

- Complete project structure overview
- Common commands and workflows
- Release process (always use ./scripts/release.sh)
- Architecture details and optimizations
- Linting, testing, and CI/CD guides
- Troubleshooting tips

This file provides context for Claude Code to work more effectively
with the project without repeating instructions.

* Add CHANGELOG.md for release tracking

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

* chore: add uv.lock for reproducible builds

- Add exception in .gitignore for uv.lock
- Commit uv.lock to ensure reproducible dependency resolution
- Required for CI/CD workflows using 'uv sync --locked'

* RELEASE: v0.3.1

This release updates:
- version.py: 0.3.0 → 0.3.1
- CHANGELOG.md: Added release section for v0.3.1

After merging this PR:
- publish.yml workflow will trigger automatically
- Package will be built and published to PyPI
- GitHub release will be created with tag v0.3.1

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: vilsonrodrigues

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.3.1] - 2025-12-02
+
 ## [0.3.0] - 2025-12-02
 
 ### Added

src/msgspec_ext/version.py

@@ -1 +1 @@
-__version__ = "0.3.0"
+__version__ = "0.3.1"