Replace lint/test/docker workflows with ci.yml (gitleaks, lint, test-unit, test-integration, test-mcp, build-and-push, docs-check, security). Rebuild the Dockerfile as a digest-pinned multi-stage uv build running as uid 1000, add .dockerignore, a hardened compose file and a gitleaks config. The integration harness now falls back to /etc/hostname and /proc/self to find its own container.