v1.15.3

Enhancements

• build: Add Nix flake packaging so the CLI can be installed and run on Nix and NixOS (#174)
  The flake builds the CLI with buildGoModule, installs Bash, Zsh, and Fish
  completions, and exposes nix run, nix profile install, an overlays.default
  for NixOS and Home Manager, and a nix develop shell. Non-flake default.nix
  and shell.nix shims are provided for systems without flakes enabled. A
  homeManagerModules.default declares profiles under ~/.dash0: static tokens
  are read from authTokenFile at activation time and OAuth profiles are seeded
  for dash0 login, with runtime-acquired tokens preserved across rebuilds.
  A pre-built binary is published to a Nix User Repository for a compile-free
  install on small or non-x86_64 machines.