ci: make e2e tests resilient to CI resource contention

E2E specs spin up Docker containers in parallel and intermittently time
out waiting for UI elements under shared-runner load. Limit parallel
workers to 2 and retry flaky failures twice so the container job can
complete and publish the PR preview image.

package.json

@@ -36,7 +36,7 @@
     "scripts:update-readme-integrations": "tsx ./scripts/update-integration-list.mts",
     "start": "concurrently \"pnpm with-env node apps/tasks/tasks.cjs\" \"pnpm with-env node apps/websocket/wssServer.cjs\" \"pnpm -F nextjs start\"",
     "test": "cross-env NODE_ENV=development CI=true vitest run --exclude e2e --coverage.enabled ",
-    "test:e2e": "cross-env NODE_ENV=development CI=true vitest e2e",
+    "test:e2e": "cross-env NODE_ENV=development CI=true vitest e2e --retry 2 --maxWorkers 2",
     "test:ui": "cross-env NODE_ENV=development CI=true vitest --exclude e2e --ui --coverage.enabled",
     "typecheck": "turbo typecheck",
     "with-env": "dotenv -e .env --"