Pre-compile the app bundle and run tests against that

Speed difference is 3min vs 30sec to run all tests.

playwright.config.ts

@@ -84,10 +84,12 @@ const config: PlaywrightTestConfig = {
 
   webServer: [
     {
-      command: "npm run start -- --strictPort --port 3001",
+      // Use preview server (pre-built app) for main server - much faster startup
+      command: "npm run serve -- --strictPort --port 3001",
       port: 3001,
     },
     // Required by test tests/e2e/repo/commits.spec.ts "loading more commits, adds them to the commits list"
+    // Keep dev server here since it needs custom runtime config
     {
       command: "npm run start -- --strictPort --port 3002",
       port: 3002,

tests/support/globalSetup.ts

@@ -53,6 +53,13 @@ export default async function globalSetup(): Promise<() => void> {
     process.exit(1);
   }
 
+  // Build the app once before running tests to avoid compilation
+  // overhead on each worker.
+  console.log("Building the app for tests...");
+  const { execa: exec } = await import("execa");
+  await exec("npm", ["run", "build"], { stdio: "inherit" });
+  console.log("Build complete");
+
   if (!process.env.SKIP_FIXTURE_CREATION) {
     console.log(
       "Recreating static fixtures. Set SKIP_FIXTURE_CREATION to skip this",