Replace dead upstream images with custom build services; add retry logic

dtagdevsec/mailoney and dtagdevsec/elasticpot are unavailable on Docker Hub
("manifest unknown"), causing the entire deployment to abort and cascade-
interrupt all other image pulls.

- Convert smtp and elasticsearch to build services with custom Python
  honeypots: smtp emulates Postfix ESMTP (EHLO/AUTH/MAIL/RCPT logging),
  elasticsearch emulates ES 7.17 HTTP API (logs recon probes like /_cat/,
  /_cluster/, /_nodes/, /_security/)
- Both use ARG BASE_IMAGE so they participate in per-decky distro variation
- Add _compose_with_retry() to deployer: 3 attempts with exponential backoff
  (5s → 10s → 20s) for transient network failures; permanent errors
  ("manifest unknown", "pull access denied") are detected and not retried
- Update test_services.py and test_composer.py: smtp/elasticsearch moved
  from UPSTREAM_SERVICES to BUILD_SERVICES (314 tests passing)

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

templates/elasticsearch/Dockerfile

@@ -0,0 +1,13 @@
+ARG BASE_IMAGE=debian:bookworm-slim
+FROM ${BASE_IMAGE}
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    python3 \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY elasticsearch_honeypot.py /opt/elasticsearch_honeypot.py
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+EXPOSE 9200
+ENTRYPOINT ["/entrypoint.sh"]