ci: add npm run build step to unit-tests job

The prerender fix only prevents regression if the build is actually run in
CI. Without this gate, a future prerendered route that becomes unreachable
behind auth would fail silently until someone runs the build manually.

Fits after the test step in the existing unit-tests job — no new job needed
since node_modules is already cached for the Playwright container.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -40,6 +40,10 @@ jobs:
         run: npm test
         working-directory: frontend
 
+      - name: Build frontend
+        run: npm run build
+        working-directory: frontend
+
       - name: Upload screenshots
         if: always()
         uses: actions/upload-artifact@v4

frontend/src/routes/hilfe/transkription/+page.ts

@@ -1,3 +1 @@
-// Safe: handleAuth in hooks.server.ts redirects unauthenticated requests
-// before prerendered HTML is visible.
 export const prerender = true;

frontend/svelte.config.js

@@ -6,7 +6,10 @@ const config = {
 	// Consult https://svelte.dev/docs/kit/integrations
 	// for more information about preprocessors
 	preprocess: vitePreprocess(),
-	kit: { adapter: adapter() }
+	kit: {
+		adapter: adapter(),
+		prerender: { entries: ['/hilfe/transkription'] }
+	}
 };
 
 export default config;