refactor(controlplane): DUCKGRES_K8S_HOT_IDLE_TTL -> WORKER_DEFAULT_T… #661

Job	Run time
build (macos-latest, darwin, arm64)	2m 7s
build (macos-15, darwin, amd64)	2m 7s
build (ubuntu-latest, linux, amd64)	1m 44s
build (ubuntu-24.04-arm, linux, arm64)	1m 30s
release	49s
	8m 17s

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