Gwtar: a static efficient single-file HTML format

Gwtar is a new HTML archival format that solves the trilemma of being static (self-contained), single-file, and efficient (lazy-loading) simultaneously. It works by creating a polyglot file: an HTML+JavaScript header followed by a tarball of assets. The JavaScript uses `window.stop()` to halt initial loading, then serves assets via HTTP range requests into the embedded tarball. This allows archiving even gigabyte-sized web pages as a single file that only downloads assets as needed, without requiring special server software or future compatibility concerns.