ca5a42314f
Phase 2 of distributed probing: - Extract check logic into standalone RunCheck() for use by probes - Add probe cluster mode: stateless nodes that fetch assignments, execute checks, and report results to the leader - Add multi-node result aggregation with configurable strategy (any-down, majority-down, all-down) - Leader ingests probe results into engine live state and triggers alerts - New env vars: UPKEEP_NODE_ID, UPKEEP_NODE_NAME, UPKEEP_NODE_REGION, UPKEEP_AGG_STRATEGY - Example docker-compose.probe.yml with leader + 2 regional probes