Fix CI failures on Windows by using cross-platform copy-assets script

Replace Unix shell commands (cp, mkdir -p) with a Node.js script that
uses fs.copyFileSync/cpSync, which works on all platforms.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ozgesolidkey

package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "postinstall": "npx @electron/rebuild",
     "build": "tsc && npm run copy-assets",
-    "copy-assets": "cp src/renderer/index.html src/renderer/styles.css dist/renderer/ && cp -r src/renderer/assets dist/renderer/ && mkdir -p dist/renderer/lib && cp node_modules/xterm/css/xterm.css dist/renderer/lib/ && cp node_modules/xterm/lib/xterm.js dist/renderer/lib/ && cp node_modules/xterm-addon-fit/lib/xterm-addon-fit.js dist/renderer/lib/ && cp node_modules/marked/lib/marked.umd.js dist/renderer/lib/",
+    "copy-assets": "node scripts/copy-assets.js",
     "start": "npm run build && electron .",
     "dev": "npm run build && electron .",
     "watch": "tsc -w",

scripts/copy-assets.js

@@ -0,0 +1,30 @@
+const fs = require('fs');
+const path = require('path');
+
+const root = path.resolve(__dirname, '..');
+
+function copyFile(src, destDir) {
+  fs.mkdirSync(destDir, { recursive: true });
+  fs.copyFileSync(
+    path.join(root, src),
+    path.join(root, destDir, path.basename(src))
+  );
+}
+
+function copyDir(src, dest) {
+  fs.cpSync(path.join(root, src), path.join(root, dest), { recursive: true });
+}
+
+// src/renderer/index.html, styles.css → dist/renderer/
+copyFile('src/renderer/index.html', 'dist/renderer');
+copyFile('src/renderer/styles.css', 'dist/renderer');
+
+// src/renderer/assets/ → dist/renderer/assets/
+copyDir('src/renderer/assets', 'dist/renderer/assets');
+
+// vendor libs → dist/renderer/lib/
+const libDir = 'dist/renderer/lib';
+copyFile('node_modules/xterm/css/xterm.css', libDir);
+copyFile('node_modules/xterm/lib/xterm.js', libDir);
+copyFile('node_modules/xterm-addon-fit/lib/xterm-addon-fit.js', libDir);
+copyFile('node_modules/marked/lib/marked.umd.js', libDir);