v0.86.0: Phase 2 managed updates — floor-driven auto-update

The controller honors an operator-enforced minimum version (FLOOR) on the hub
report ACK and auto-updates to the floor when below it (managed default, no click),
reusing the Phase 1 in-guest-pull + agent-swap + rollback. Latest stays the opt-in
button; the floor is the auto-target, never latest.

- pusher.go: PushResponse += min_controller_version, latest_version (existing ACK seam)
- main.go: OnPushResponse → updater.SetFloor + MaybeAutoUpdate (rides report cycle)
- updater.go: SetFloor/GetFloor + MaybeAutoUpdate reusing performUpdate (auto-floor);
  no-op at/above floor, floor>latest, dev/no-agent/backup; no flap (in-mem+persisted)
- settings UI (HU): floor display + auto restart-poll during an auto-update
- tests: below/at/floor>latest/no-flap/raised-floor; below-floor red-proof verified
- no agent change (reuses Phase 1 POST /controller/swap)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FSZmmSFVzGwEzhYmxbkgBK

controller/internal/web/templates/settings.html

@@ -99,6 +99,21 @@
                 {{if .AutoUpdateEnabled}}<span class="state-text-green">✅ Aktív</span> <span class="mono">({{.AutoUpdateTime}})</span>{{else}}–{{end}}
             </span>
         </div>
+        {{if .ControllerFloor}}
+        <div class="settings-row">
+            <span class="settings-label">Minimális verzió (üzemeltető)</span>
+            <span class="settings-value mono">
+                {{.ControllerFloor}}
+                <span style="margin-left:0.5em; color:#888;">— a rendszer automatikusan erre a verzióra frissít, ha régebbi</span>
+            </span>
+        </div>
+        {{end}}
+        {{if .UpdateRunning}}
+        <div class="settings-row">
+            <span class="settings-label">Állapot</span>
+            <span class="settings-value state-text-yellow" id="auto-update-status">⏳ Frissítés folyamatban — a vezérlő hamarosan újraindul…</span>
+        </div>
+        {{end}}
         {{with .LastUpdateState}}
         <div class="settings-row">
             <span class="settings-label">Utolsó frissítés</span>
@@ -192,6 +207,12 @@ function pollUntilBack() {
             .catch(function() {});
     }, 3000);
 }
+
+// If an update is already in flight when the page loads (e.g. a floor-driven AUTO-update kicked off by
+// the hub, not a button click), surface the same restart-poll panel so the page recovers itself.
+{{if .UpdateRunning}}
+pollUntilBack();
+{{end}}
 </script>
 
 <!-- Section: Storage Paths -->