hub: F2 — alert on host already degraded/stale at (re)start (seed only healthy) v0.21.0

Constructors seed only healthy hosts; an already-degraded/stale host is left unseeded so the first
Check() emits once (cooldown dedups on hub restart). Born-degraded red-proof + staleness test updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pg8ANF97SEeKYSN5Jxw3qJ

hub/internal/monitor/host_capability.go

@@ -53,14 +53,17 @@ func NewHostCapabilityChecker(s *store.Store, onEvent EventNotifyFunc, logger *l
 		}
 		cc.customerOf[row.HostID] = row.CustomerID
 		st, _, _ := capabilityState(row.Capabilities)
-		cc.states[row.HostID] = st
+		// F2: seed only HEALTHY hosts. A host already degraded at (re)start is left UNSEEDED so the
+		// first Check() observes oldState=="" and emits once — otherwise a box already broken when the
+		// hub restarts would stay silent forever. The dispatcher's 1h cooldown dedups the re-emit.
 		if st == "degraded" {
 			degCount++
-		} else {
-			okCount++
+			continue
 		}
+		cc.states[row.HostID] = st
+		okCount++
 	}
-	logger.Printf("[INFO] Host capability checker initialized: %d ok, %d degraded", okCount, degCount)
+	logger.Printf("[INFO] Host capability checker initialized: %d ok, %d degraded (degraded left unseeded → first Check emits)", okCount, degCount)
 	return cc
 }
 
@@ -87,7 +90,14 @@ func (cc *HostCapabilityChecker) Check() {
 		newState, names, features := capabilityState(row.Capabilities)
 		oldState := cc.states[row.HostID]
 		if oldState == "" {
-			cc.states[row.HostID] = newState // first observation — no event
+			// F2: first observation (incl. a hub restart). A healthy first-obs seeds silently; a host
+			// already DEGRADED at first sight emits once (else a host that was already broken when the
+			// hub (re)started would never alert). The dispatcher's 1h operator cooldown dedups a re-emit
+			// across a hub restart.
+			cc.states[row.HostID] = newState
+			if newState == "degraded" {
+				cc.emitTransition(row.HostID, row.CustomerID, "unknown", newState, names, features)
+			}
 			continue
 		}
 		if oldState == newState {