fix(ci): add Redis sidecar with bash /dev/tcp readiness wait

K8s executor doesn't wait for service containers to be healthy.
Use bash built-in /dev/tcp for readiness check (no netcat needed).
Remove --skip for redis_integration_test since sidecar provides Redis.

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

.gitlab-ci.yml

@@ -86,11 +86,22 @@ 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/:$//')
     - nvidia-smi  # verify GPU access
-    - cargo test --workspace --lib -- --skip model_loader::tests --skip persistence::redis_integration_test
+    # Wait for Redis sidecar (K8s executor doesn't wait for service readiness)
+    - |
+      for i in $(seq 1 30); do
+        if bash -c 'echo PING > /dev/tcp/localhost/6379' 2>/dev/null; then
+          echo "Redis ready"; break
+        fi
+        echo "Waiting for Redis... ($i/30)"; sleep 1
+      done
+    - cargo test --workspace --lib -- --skip model_loader::tests
 
 # --------------------------------------------------------------------------
 # Stage 3: Build + push service images (main only, Kaniko → GitLab registry)