feature(starnet): add starnet to siril to use ml models for star removal, this needs nix-ld to be enabled

modules/nixos/astro.nix

@@ -6,4 +6,18 @@
     stellarium
     siril
   ];
+
+  # StarNet++ has no nixpkgs package. Download the StarNet v2 ORT CLI build
+  # (starnet2_linux_*_ORT_x64_cli) from https://www.starnetastro.com/download/
+  # and unzip it to ~/.local/share/siril/starnet/. Then in Siril set
+  #   Preferences -> Miscellaneous -> StarNet executable
+  # to the extracted ./starnet2 binary.
+  #
+  # The binary is a generic dynamically-linked ELF, so NixOS needs nix-ld to
+  # run it. Its own opencv/onnxruntime libs are found via the bundled ./lib.
+  programs.nix-ld.enable = true;
+  programs.nix-ld.libraries = with pkgs; [
+    stdenv.cc.cc.lib   # libstdc++ / libgcc_s
+    zlib
+  ];
 }