v0.2.1

## What's changed - Added Ghostty-style project opening through the Termy CLI: `termy /path/to/project` and `termy --working-directory /path/to/project`. - Wired startup argument handling so launched Termy windows use the requested working directory. - Continued libtermy/FFI work by exposing runtime/config data needed by embedders and updating the docs. - Bumped the app and CLI packages to `0.2.1`. ## Validation - `cargo fmt` - `cargo test -q -p termy_cli open_` - `cargo test -q -p termy startup_arguments` - `cargo check --workspace`