Add Docker build, K8s manifests, and CI/CD deploy pipeline

- Dockerfile: multi-stage build with $BUILDPLATFORM for native Maven
  builds on ARM64 runners, amd64 runtime target. Passes REGISTRY_TOKEN
  build arg for cameleer3-common dependency resolution.
- K8s manifests: ClickHouse StatefulSet with init scripts ConfigMap,
  server Deployment + NodePort (30081)
- CI: docker job (QEMU + buildx cross-compile, registry cache,
  provenance=false, old image cleanup) + deploy job (kubectl)
- .dockerignore for build context optimization

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

.dockerignore

@@ -0,0 +1,10 @@
+**/target/
+.git/
+.gitea/
+.idea/
+*.iml
+docs/
+*.md
+!pom.xml
+.planning/
+.claude/