Cleanup PR

Author: sea-snake

vitest.config.ts

@@ -20,6 +20,13 @@ export default defineConfig(
       globals: true,
       watch: false,
       setupFiles: "./src/frontend/test-setup.ts",
+      // Make sure that our browser e2e tests run one by one:
+      // - `sequence.concurrent: false` within each test file
+      // - `fileParallelism: false` across test files
+      //
+      // This makes sure that WebdriverIO won't start more than one browser
+      // instance at the same time, which would result in the following error:
+      // `Could not start browser after 5 retries: Error: spawn ETXTBSY`
       sequence: {
         concurrent: false,
       },