[rmkr-dev]

Adds a Skillbook entry and a matching Promptbook entry for making Spring for Apache Kafka consumers reliable in production.

Skill: spring-kafka-consumer-reliability-guardrails

• At-least-once by default: idempotent handlers on a dedupe key, with an inbox table (and outbox for emitted events) in the same DB transaction
• Auto-commit off, offsets committed after work; BATCH vs RECORD vs MANUAL_IMMEDIATE chosen on purpose
• One DefaultErrorHandler with bounded exponential backoff, explicit non-retryable exceptions, and a DeadLetterPublishingRecoverer to an owned DLT with partitions ≥ source
• ErrorHandlingDeserializer for poison pills; @RetryableTopic only when per-key ordering doesn't matter (and never on batch listeners)
• max.poll.records sized against max.poll.interval.ms, concurrency × replicas ≤ partitions, cooperative-sticky rebalances, static membership, shutdown inside the pod grace period
• Micrometer lag/retry/DLT/dedupe metrics with bounded tags plus broker-side group lag, failure-path tests on Testcontainers or @EmbeddedKafka, SASL_SSL with credentials only from secrets
• Copilot / Claude Code / Codex placement notes and a SKILL.md stub

Prompt: harden-spring-kafka-consumer

• Consumer hardening pass with placeholders, a ranked findings list, a failure-path test matrix, and an exception classification table, topic table, and poll-budget math in the output

Catalogs go to 35 skills / 35 prompts. node scripts/site-check.mjs passes locally.