Fastmash 0.2.0

Added

• Homebrew installation on Linux x86-64 through pederbe/tap/fastmash,
  with both executables, license notices and installed system-sort checks.
  Source recipes for Nix and Fedora are also prepared; their repository
  admission remains pending.
• Native Apple Silicon macOS 15 and later, with built-in sorting and disk spill.
  Release archives include license notices, checksums and build provenance.
  Installation and command checks run against the same archive on macOS 15
  and 26 before and after release upload.

Fixed

• Keep the website's installation panel stable during loading and defer its
  script, while retaining every installation command without JavaScript.
• Keep documentation code examples readable in light mode without JavaScript.

Changed

• Native sorted calculations and sorted rmdup on Linux and macOS report
  missing named-key input headers and read failures themselves, without
  starting the system sort or Sort supervisor. Missing headers now use the
  native diagnostic on Linux; read errors take precedence, while a command
  containing wmean still succeeds without output at clean empty input.
• Give the documentation clearer headings and navigation, distinct example,
  table and diagram panels, and a card layout for the existing starting links.