docs: add open source community files and README badges

Add LICENSE, CONTRIBUTING, CHANGELOG, SECURITY, CODE_OF_CONDUCT,
GitHub issue/PR templates, CODEOWNERS. Update package.json with
license/repo/author metadata. Add badges and logo to README.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -0,0 +1,42 @@
+# 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).
+
+## [0.3.2] - 2026-03-07
+
+### Fixed
+- Update docker-compose only after Docker image is pushed
+
+## [0.3.1] - 2026-03-07
+
+### Fixed
+- Include tags in sync pull response and update API spec
+
+### Changed
+- Update FEATURES.md, DEPLOYMENT.md, and CLAUDE.md documentation
+
+## [0.3.0] - 2026-03-06
+
+### Added
+- Tag management system with auto-extraction from note content
+- Full-text search across titles, content, and tags
+- Dark mode with system preference detection
+- Note pinning, archive, and trash workflows
+- Image attachments with drag-and-drop upload
+- 12 color themes for note cards
+- PWA support with offline-first IndexedDB sync
+- LWW CRDT-based conflict resolution
+- Docker deployment with multi-stage build
+- CI/CD pipeline with GitHub Actions
+- Comprehensive E2E test suite with Playwright
+- OpenAPI spec and auto-generated API docs
+
+### Changed
+- Initial public release
+
+[0.3.2]: https://github.com/bretzel-app/crumbs/compare/v0.3.1...v0.3.2
+[0.3.1]: https://github.com/bretzel-app/crumbs/compare/v0.3.0...v0.3.1
+[0.3.0]: https://github.com/bretzel-app/crumbs/releases/tag/v0.3.0