v1.0.2

feat: add CLI version and self-update commands

- add version and autoupdate subcommands to the Cobra CLI
- inject runtime version and update dependencies through the CLI
- download the latest GitHub release for the current OS and arch
- verify release binaries with SHA-256 checksums before replacing
- skip updates when the installed version already matches the release
- cover update success, skip, and checksum failure paths in tests
- trim stale docs links from the README and point to the license