chore: bump version to 0.4.0

New in 0.4.0:
- --version flag
- Security: random auth token, path-based cache delete, PRAGMA blocked
- CORS: POST methods, localhost origin, auth headers
- Safelist: fail closed on load error
- Accuracy tests for dir sizes and symlinks
- Remove dead code (query_dirs_by_name)

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

chore: bump version to 0.3.0

New in 0.3.0:
- Safelist: keep/unkeep/keep-list to protect files from deletion
- Accurate directory sizes in default scan mode (small files counted)
- Scan mode shown in output (default vs full)
- Web UI filters out deleted files

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

feat: add examples to CLI help output

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

ci: add GitHub Actions release pipeline for macOS binaries

Builds aarch64 + x86_64 binaries on tag push, publishes to GitHub Releases.
Update README with one-line install from releases.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>