fix(ci): add Redis service for integration tests

Redis sidecar runs as additional container in the build pod.
Kubernetes executor shares network namespace, so tests can
reach Redis at localhost:6379.

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

.gitlab-ci.yml

@@ -86,6 +86,9 @@ test:
   extends: .rust-base
   stage: test
   needs: [check]
+  services:
+    - name: redis:7-alpine
+      alias: redis
   script:
     # Remove CUDA stubs from LD_LIBRARY_PATH — nvidia RuntimeClass provides real libcuda.so
     - export LD_LIBRARY_PATH=$(echo "$LD_LIBRARY_PATH" | tr ':' '\n' | grep -v stubs | tr '\n' ':' | sed 's/:$//')