nix: initial tooling; add NixOS module

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I5ff8dfa450ec405e2ead5d16e0de90856a6a6964

nix/package.nix

@@ -0,0 +1,71 @@
+{
+  lib,
+  stdenv,
+  nodejs,
+  pnpmConfigHook,
+  fetchPnpmDeps,
+  pnpm,
+  makeBinaryWrapper,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "troutbot";
+  version = "0-unstable-2026-01-30";
+
+  src = lib.fileset.toSource {
+    root = ../.;
+    fileset = lib.fileset.unions [
+      ../src
+      ../config.example.ts
+      ../package.json
+      ../pnpm-lock.yaml
+      ../tsconfig.json
+    ];
+  };
+
+  strictDeps = true;
+  nativeBuildInputs = [
+    nodejs # in case scripts are run outside of a pnpm call
+    pnpmConfigHook
+    pnpm # at least required by pnpmConfigHook, if not other (custom) phases
+
+    makeBinaryWrapper
+  ];
+
+  pnpmDeps = fetchPnpmDeps {
+    inherit (finalAttrs) pname version src;
+    fetcherVersion = 3;
+    hash = "sha256-y8LV1D+EgGcZ79lmxS20dqYBPEfk4atma+RWf7pJI30=";
+  };
+
+  buildPhase = ''
+    runHook preBuild
+
+    pnpm run build --outDir dist
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/{bin,share}
+
+    # Copy transpiled result
+    cp -rv dist/* $out/share
+
+    # Copy the example config
+    install -Dm755 config.example.ts $out/share
+
+    makeWrapper ${lib.getExe nodejs} $out/bin/troutbot \
+      --set-default NODE_ENV production \
+      --add-flags "$out/share/index.js"
+
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "The ultimate trout population helper";
+    license = lib.licenses.eupl12;
+    maintainers = with lib.maintainers; [NotAShelf];
+  };
+})