ci: retry flaky container-backed unit tests in fast gate

Integration tests (nzbget, nextcloud, pi-hole, etc.) start Docker
containers and intermittently time out under shared-runner load, which
fails the fast gate and skips the container job that publishes the PR
preview image. Retry failing unit tests twice so transient container
startup failures do not block the image publish.

package.json

@@ -46,7 +46,7 @@
     "scripts:update-bug-report-template": "tsx ./scripts/update-bug-report-template.mts",
     "scripts:update-readme-integrations": "tsx ./scripts/update-integration-list.mts",
     "start": "pnpm -F nextjs start",
-    "test": "cross-env NODE_ENV=development CI=true vitest run --project \"!e2e\" --coverage.enabled ",
+    "test": "cross-env NODE_ENV=development CI=true vitest run --project \"!e2e\" --retry 2 --coverage.enabled ",
     "test:e2e": "cross-env NODE_ENV=development CI=true vitest e2e --retry 2 --maxWorkers 2",
     "test:workshop": "sh apps/workshop/test.sh",
     "test:workshop-image": "sh apps/workshop/test-image.sh",