Fix Cross platform building of Draupnir

apps/draupnir/scripts/write-build-info.cjs

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2026 Catalan Lover <catalanlover@protonmail.com>
+//
+// SPDX-License-Identifier: 0BSD
+
+// Cross-platform replacement for the old mv/rm shell one-liners (Windows cmd.exe has neither).
+const { execSync } = require("node:child_process");
+const fs = require("node:fs");
+const path = require("node:path");
+
+const targets = {
+  version: {
+    command: "git describe",
+    file: path.join(__dirname, "..", "version.txt"),
+  },
+  branch: {
+    command: "git rev-parse --abbrev-ref HEAD",
+    file: path.join(__dirname, "..", "branch.txt"),
+  },
+};
+
+function writeBuildInfo(target) {
+  const { command, file } = targets[target];
+  try {
+    const output = execSync(command, { encoding: "utf-8" }).trim();
+    fs.writeFileSync(file, output + "\n");
+  } catch {
+    // git may be unavailable, this may not be a repo, or there may be no tags/HEAD.
+    // config.ts already falls back to package.json's version / a default message.
+  }
+}
+
+const target = process.argv[2];
+if (!targets[target]) {
+  console.error(
+    `Usage: node write-build-info.cjs <${Object.keys(targets).join("|")}>`
+  );
+  process.exit(1);
+}
+writeBuildInfo(target);