feat: add pre-baked CI build images

- cameleer-build:1 — Maven 3.9 + Java 17 + Node.js 22 + curl/jq/procps/bc
- cameleer-docker-builder:1 — Docker 27 + git/curl/jq

Eliminates per-build tool installation across cameleer3 and cameleer3-server.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-builder/Dockerfile

@@ -0,0 +1,3 @@
+FROM docker:27
+
+RUN apk add --no-cache git curl jq