feat(chat): refine parent-child chunk replacement logic in merge process #367

Job	Run time
build-sandbox	21s
build-app (amd64, linux/amd64, ubuntu-latest)	5m 53s
build-ui	22s
build-app (arm64, linux/arm64, ubuntu-24.04-arm)	5m 22s
build-docreader	4m 31s
merge	20s
	16m 49s

Provide feedback