allow multiple dev windows

js/src/main.ts

@@ -25,11 +25,21 @@ if (process.platform === 'darwin' && !app.isPackaged) {
   app.dock?.setIcon(path.join(__dirname, '../../assets/icon.png'));
 }
 
+// In dev, `LLINK_PROFILE=foo yarn start` spins up a second instance with an
+// isolated userData dir so it can coexist with the default one (separate auth,
+// cookies, leveldb locks).
+const devProfile = !app.isPackaged ? process.env.LLINK_PROFILE : undefined;
+if (devProfile) {
+  app.setPath('userData', `${app.getPath('userData')}-${devProfile}`);
+}
+
 // Single-instance lock: on Windows/Linux, clicking a llink:// URL launches a new
 // process. The lock makes the losing instance quit and fires `second-instance` on
 // the primary, so we focus the existing window instead of spawning a duplicate.
 // macOS uses `open-url` instead and doesn't need this, but the lock is harmless.
-if (!app.requestSingleInstanceLock()) {
+// Skip the lock when running a named dev profile — those instances are meant to
+// run alongside the default one.
+if (!devProfile && !app.requestSingleInstanceLock()) {
   app.quit();
 }