fix(e2e): copy webapp/dist to backend embed location before build

The Go binary embeds static files from backend/cmd/community/web/dist
via go:embed directive. The e2e-tests workflow was building the frontend
in webapp/dist but not copying it to the embed location before compiling,
resulting in an empty app (no Vue frontend loaded).

This commit adds the missing copy step, matching the Dockerfile build process.

.github/workflows/e2e-tests.yml

@@ -80,6 +80,11 @@ jobs:
           cp -r backend/locales .
           cp -r backend/templates .
 
+      - name: Copy frontend dist for embed
+        run: |
+          mkdir -p backend/cmd/community/web/dist
+          cp -r webapp/dist/* backend/cmd/community/web/dist/
+
       - name: Start Ackify server
         env:
           ACKIFY_DB_DSN: "postgres://postgres:testpassword@localhost:5432/ackify_test?sslmode=disable"