v2.6.1

Changed

• Improved external browser authentication so --browser chooses Chrome first, then Firefox, then the system default browser.
• Improved NixOS prebuilt package integration for launching helper binaries and desktop services.
• Updated the release process to publish GitHub release notes from the changelog.

Fixed

• Fixed NixOS GUI launch failures caused by package-local binary paths.
• Fixed NixOS tray icon setup documentation for GNOME desktops.
• Fixed browser authentication for portals that require a client certificate.
• Fixed release automation so Nix flake hash updates are run manually after release assets are available.