fix(adminfront): fix playwright webserver timeout by refining preview command and vite config

scripts/run_adminfront_ci_tests.sh

@@ -295,7 +295,7 @@ fi
 echo "==> adminfront using PORT=$port"
 (
   cd "$tmp_dir/adminfront"
-  PORT="$port" PLAYWRIGHT_WORKERS="${PLAYWRIGHT_WORKERS:-1}" \
+  CI=true PORT="$port" PLAYWRIGHT_WORKERS="${PLAYWRIGHT_WORKERS:-1}" \
     pnpm exec playwright test "${playwright_project_args[@]}"
 ) 2>&1 | tee reports/adminfront-test.log
 test_exit_code=${PIPESTATUS[0]}