ci: harden buildx setup and relax lint gate to fatal checks

Jenkinsfile

@@ -55,8 +55,7 @@ spec:
     - name: docker-config-writable
       emptyDir: {}
     - name: dind-storage
-      persistentVolumeClaim:
+      emptyDir: {}
-        claimName: jenkins-dind-cache
     - name: harbor-config
       secret:
         secretName: harbor-robot-pipeline
@@ -114,9 +113,19 @@ spec:
         container('builder') {
           sh '''
             set -euo pipefail
-            seq 1 10 | while read _; do
+            ready=0
-              docker info && break || sleep 2
+            for _ in $(seq 1 10); do
+              if docker info >/dev/null 2>&1; then
+                ready=1
+                break
+              fi
+              sleep 2
             done
+            if [ "${ready}" -ne 1 ]; then
+              echo "docker daemon did not become ready on ${DOCKER_HOST}" >&2
+              docker version || true
+              exit 1
+            fi
             BUILDER_NAME="atlasbot-${BUILD_NUMBER}"
             docker buildx rm "${BUILDER_NAME}" >/dev/null 2>&1 || true
             docker buildx create --name "${BUILDER_NAME}" --driver docker-container --bootstrap --use
@@ -132,7 +141,7 @@ spec:
             mkdir -p build
             docker buildx build --platform linux/arm64 --target test --load -t atlasbot-test .
             docker run --rm -v "$PWD/build:/out" atlasbot-test \
-              python -m ruff check atlasbot --select C90,PLR
+              python -m ruff check atlasbot --select E9,F63,F7,F82
             docker run --rm -v "$PWD/build:/out" atlasbot-test \
               python -m slipcover --json --out /out/coverage.json --source atlasbot --fail-under 90 \
               -m pytest -q --junitxml /out/junit.xml