Child of #695 (plan sections 4.3 to 4.8, Phase 1 + 2). First the free Phase A prune: from one node per venue, 300 pings to each provider public endpoint (gra.proof.ovh.net, fsn.icmp.hetzner.com, Azure westeurope blob TCP handshake, AWS reachability, gcping europe-west1); drop regions with min RTT over 25 ms from every venue (gate G1: at least 3 regions survive).
Then the full campaign with hydraprobe from probe nodes at all venues (cloud-seven, rupelmonde, ad6, nerdland, gallo-romeins-museum, sint-niklaas-tourism-office, plus mobile-kit opportunistically per uplink) on three paths: raw WAN, tunnel via hub, tunnel direct. 10 minute runs, 3 daily windows (09:00-11:00, 13:00-16:00, 19:00-22:00), at least 2 days including 1 weekend day, minimum 6 runs per venue x region x path. Gateway CPU sampled on every B2 run per #402. Commit every result YAML.
Gate G2, the decision gate of the whole plan: at least one region passes the 4.7 thresholds at all SIX fixed target venues on the path heads will use. Related: #42, #397, #402.