integration: return HTTP 404 for unmatched URLs and close remaining browser-gate gaps

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/app.routes.server.spec.ts

@@ -0,0 +1,19 @@
+import { RenderMode } from '@angular/ssr';
+import { serverRoutes } from './app.routes.server';
+
+describe('server routes', () => {
+  it('returns HTTP 404 from the catch-all and leaves prerendered routes without a status', () => {
+    const catchAll = serverRoutes.find((route) => route.path === '**');
+
+    expect(catchAll?.renderMode).toBe(RenderMode.Server);
+    expect(catchAll && 'status' in catchAll ? catchAll.status : undefined).toBe(404);
+
+    const prerendered = serverRoutes.filter((route) => route.path !== '**');
+    expect(prerendered.length).toBeGreaterThan(0);
+
+    for (const route of prerendered) {
+      expect(route.renderMode, route.path).toBe(RenderMode.Prerender);
+      expect('status' in route, `${route.path} must not set status`).toBe(false);
+    }
+  });
+});