chore: endpoint request header follow up and docs #224

Job	Run time
Basic checks	53s
Build and publish artifacts and plugins locally	2m 46s
Run annotation processor tests	1m 36s
Check service docker image contents	1m 8s
Run sbt test	4m 11s
Maven samples (shopping-cart-quickstart, true)	42s
Maven samples (choreography-saga-quickstart, true)	1m 10s
Maven samples (doc-snippets, false)	30s
Maven samples (view-store, true)	1m 18s
Maven samples (spring-dependency-injection, true)	47s
Maven samples (event-sourced-customer-registry, true)	51s
Maven samples (event-sourced-counter-brokers, docker compose up -d, true)	1m 30s
Maven samples (event-sourced-customer-registry-subscriber, true, ./start-upstream.sh)	1m 5s
Maven samples (key-value-counter, true)	43s
Maven samples (key-value-shopping-cart, true)	41s
Maven samples (key-value-customer-registry, true)	57s
Maven samples (tracing, false)	28s
Maven samples (reliable-timers, true)	43s
Maven samples (transfer-workflow, true)	44s
Maven samples (transfer-workflow-compensation, true)	48s
	23m 31s

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