Add script for linux build targets

scripts/prepare_linux_build.js

@@ -0,0 +1,30 @@
+// Copyright 2025 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+const fs = require('node:fs');
+const _ = require('lodash');
+
+const TARGETS = new Set(['appimage', 'deb']);
+
+const targets = (process.argv[2] || '').split(',');
+if (
+  targets.length === 0 ||
+  !targets.every(target => TARGETS.has(target.toLowerCase()))
+) {
+  console.error(
+    `Invalid linux targets ${targets}. Valid options: ${[...TARGETS]}`
+  );
+  process.exit(1);
+}
+
+const { default: packageJson } = require('./packageJson.js');
+
+console.log('prepare_linux_build: updating package.json');
+
+// ------
+
+_.set(packageJson, 'build.linux.target', targets);
+
+// -------
+
+fs.writeFileSync('./package.json', JSON.stringify(packageJson, null, '  '));