v0.1.3

Fix release builds and README for all platforms

- Add aarch64-apple-darwin (Apple Silicon) build target to release.yml
- Use macos-13 for Intel macOS builds (macos-latest is now ARM64)
- Add Windows platform to README pre-built binaries section
- Bump version to 0.1.3

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

v0.1.2

Fix RobotDB header magic length mismatch.

This aligns the on-disk magic constant with the 8-byte header field so release builds compile successfully and file header serialization remains consistent.

Made-with: Cursor