Deletes agent_client.go, agent_client_test.go, and the discovery-compare
diagnostic CLI. Removes Tick/PickBuckets/processOneBucket/processBucketResponse
from Service; renames NewServiceWithCrawler to NewService. Drops BatchSize,
ForwardMonths, AgentDiscovery config fields and their env reads. PickStaleBuckets
and UpdateBucketQueried removed from Repository interface (no callers). Stats
hardcodes forwardMonths=12. /tick route removed; /crawl is now the only machine
path, still protected by requireTickToken middleware.
vikingowl
3add4fb7ad