Fix Kafka Connect consumer override config

[jruaux]

Summary

• enable Kafka Connect connector client overrides in the standalone worker config
• use consumer.override.auto.offset.reset so the file sink's latest offset reset setting is applied
• update the sample docs to match

Verification

• docker compose config
• local smoke test confirmed Kafka Connect logs show auto.offset.reset = latest and records are written to output/dw-scte.jsonl

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Note

Low Risk
Documentation and sample-only Docker/Connect configuration; no production service or auth changes.

Overview
Adds a Kafka Connect sample under samples/kafka-connect that runs Korvet with Redis, a standalone Connect worker, a built-in file sink, and a looping JSON producer on topic dw-scte, with Makefile helpers and docs linked from the root and samples READMEs. Generated sink output is gitignored via samples/kafka-connect/output/.

Connect behavior is tuned so connector consumer settings actually apply: the worker sets connector.client.config.override.policy=All, and the file sink uses consumer.override.auto.offset.reset=latest (documented in the sample README) so the sink starts at latest offsets instead of ignoring a non-prefixed override.

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