syz-agent: add agentic server #18645

Job	Run time
dashboard	2m 8s
old	7m 28s
aux	4m 3s
arch (presubmit_arch_netbsd)	3m 59s
build	3m 56s
race	8m 50s
race_dashboard	3m 18s
arch (presubmit_arch_openbsd)	3m 48s
arch (presubmit_arch_windows)	3m 39s
arch (presubmit_arch_freebsd)	6m 24s
arch (presubmit_arch_executor)	3m 18s
arch (presubmit_arch_linux)	10m 49s
arch (presubmit_arch_darwin)	3m 49s
gvisor	4m 1s
	1h 9m 30s

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