controller v0.47.0: backups page — whole-guest backup visibility + manual trigger

Part 2 of the USB/backup spec. agentapi: StatusResponse.Backup record, DueResponse
age_seconds, RestoreTestStatus(). New "Rendszermentés (teljes mentés)" section
(read-only: last backup/target PBS-vs-local/next-due/restore-test) + "Mentés most"
manual trigger that goes through the quiesce loop (controller owns quiescing):
quiesce.Loop gains mutex + TriggerNow() (single-flight, async). New
/api/guest-backup/{trigger,status} (distinct from apiRouter's /api/backup/*).
App-data rows relabeled under an "Alkalmazás-mentések" divider. Config → slice 10.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

controller/internal/web/handlers.go

@@ -512,6 +512,9 @@ func (s *Server) backupsHandler(w http.ResponseWriter, r *http.Request) {
 	data["SystemInfo"] = system.GetInfo(s.primaryHDDPath(), s.cpuCollector)
 	data["StorageBars"] = s.buildStorageBars()
 
+	// Whole-guest backup view (agent-sourced, read-only) for the "Rendszermentés" section.
+	data["GuestBackup"] = s.loadGuestBackup(r.Context())
+
 	if s.backupMgr != nil {
 		nextDBDump := scheduler.NextDailyRun(s.cfg.Backup.DBDumpSchedule)
 		fullStatus := s.backupMgr.GetFullStatus(nextDBDump)