hub v0.45.0: floor-UI separation + effective-floor source + per-box MinAgent conditional floor

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

hub/internal/web/hosts.go

@@ -2,6 +2,7 @@ package web
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"sort"
 	"time"
@@ -9,6 +10,15 @@ import (
 	"gitea.dooplex.hu/admin/felhom-hub/internal/store"
 )
 
+// agentOrUnknown renders an agent version for operator text, mapping the empty (never-reported)
+// value to a readable token.
+func agentOrUnknown(v string) string {
+	if v == "" {
+		return "unknown"
+	}
+	return v
+}
+
 // hostStatus computes the host's liveness state from its last-report recency, using the
 // SAME thresholds as the HostStalenessChecker (s.staleThreshold; "down" at 2×). This keeps
 // the GUI badge in agreement with the alerting — there is no second definition of "stale".
@@ -177,6 +187,10 @@ type hostListRow struct {
 	WorstFillPct  float64
 	WorstFillName string
 	HasStorage    bool
+	// FloorHeld (Part D): the managed controller-version floor is being WITHHELD because this box's
+	// agent is below the current golden's MinAgent. HeldReason carries the operator-facing text.
+	FloorHeld  bool
+	HeldReason string
 }
 
 // customerName resolves a display name for a customer id (config first, then the last
@@ -224,6 +238,13 @@ func (s *Server) handleHostsList(w http.ResponseWriter, r *http.Request) {
 			HasReport:    h.LastReportAt != nil,
 		}
 
+		// Part D: surface a held managed floor (agent below the golden's MinAgent) so a held box is
+		// never silently stale.
+		if fd := s.store.ResolveManagedFloor(h.CustomerID); fd.Held {
+			row.FloorHeld = true
+			row.HeldReason = fmt.Sprintf("held: agent %s < MinAgent %s", agentOrUnknown(fd.AgentVersion), fd.MinAgent)
+		}
+
 		// Guest counts from the reality table (per-host accurate).
 		guests, _ := s.store.ListGuestsForHost(h.HostID)
 		row.GuestTotal = len(guests)