v0.1.72

Streamline version management: derive from git tag

- Remove hardcoded version from cmd/root.go, use ldflags injection
- Update release workflow to inject version into Go and Xcode builds
- Update Makefile to derive version from git describe
- Update Shared.xcconfig with placeholder version
- Simplify release docs in README.md

No more manual version bumps needed - just tag and push.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>