fix(frontend): detect @lydell/node-pty prebuilts in postinstall (#673)

The postinstall script was failing on Windows because it only checked
for native binaries in the traditional node-pty/build/Release location.
This project uses @lydell/node-pty which distributes prebuilt binaries
via separate platform-specific packages (e.g., @lydell/node-pty-win32-x64).

Changes:
- Add checks for @lydell/node-pty platform-specific prebuilt packages
- Support npm workspaces by checking both local and root node_modules
- Skip unnecessary electron-rebuild when prebuilts are already available

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

apps/frontend/scripts/postinstall.cjs

@@ -93,12 +93,40 @@ function runElectronRebuild() {
  * Check if node-pty is already built
  */
 function isNodePtyBuilt() {
-  const buildDir = path.join(__dirname, '..', 'node_modules', 'node-pty', 'build', 'Release');
-  if (!fs.existsSync(buildDir)) return false;
+  // Check traditional node-pty build location (local node_modules)
+  const localBuildDir = path.join(__dirname, '..', 'node_modules', 'node-pty', 'build', 'Release');
+  if (fs.existsSync(localBuildDir)) {
+    const files = fs.readdirSync(localBuildDir);
+    if (files.some((f) => f.endsWith('.node'))) return true;
+  }
 
-  // Check for the main .node file
-  const files = fs.readdirSync(buildDir);
-  return files.some((f) => f.endsWith('.node'));
+  // Check root node_modules (for npm workspaces)
+  const rootBuildDir = path.join(__dirname, '..', '..', '..', 'node_modules', 'node-pty', 'build', 'Release');
+  if (fs.existsSync(rootBuildDir)) {
+    const files = fs.readdirSync(rootBuildDir);
+    if (files.some((f) => f.endsWith('.node'))) return true;
+  }
+
+  // Check for @lydell/node-pty with platform-specific prebuilts
+  const arch = os.arch();
+  const platform = os.platform();
+  const platformPkg = `@lydell/node-pty-${platform}-${arch}`;
+
+  // Check local node_modules
+  const localLydellDir = path.join(__dirname, '..', 'node_modules', platformPkg);
+  if (fs.existsSync(localLydellDir)) {
+    const files = fs.readdirSync(localLydellDir);
+    if (files.some((f) => f.endsWith('.node'))) return true;
+  }
+
+  // Check root node_modules (for npm workspaces)
+  const rootLydellDir = path.join(__dirname, '..', '..', '..', 'node_modules', platformPkg);
+  if (fs.existsSync(rootLydellDir)) {
+    const files = fs.readdirSync(rootLydellDir);
+    if (files.some((f) => f.endsWith('.node'))) return true;
+  }
+
+  return false;
 }
 
 /**