v0.4.0: monitoring & backup — scheduler, CPU/temp metrics, healthchecks, restic backups

Phase 2 (Monitoring & Health):
- Central job scheduler replacing ad-hoc goroutines (internal/scheduler)
- CPU usage collector via /proc/stat background sampling (internal/system/cpu_linux.go)
- Temperature reading from /sys/class/thermal + /host/sys (Docker mount)
- Load average from /proc/loadavg
- Healthchecks.io-compatible HTTP pinger (internal/monitor/pinger.go)
- System health checks: disk, memory, CPU, temp, Docker, protected containers (internal/monitor/healthcheck.go)

Phase 3 (Backups):
- Database auto-discovery via docker ps + docker inspect (internal/backup/dbdump.go)
- Database dumping via docker exec (pg_dump / mariadb-dump) with atomic writes
- Restic backup integration with auto-password generation (internal/backup/restic.go)
- Backup orchestrator: DB dumps + restic snapshots + weekly prune (internal/backup/backup.go)
- Manual backup trigger via dashboard button and POST /api/backup/run

Dashboard UI:
- CPU usage bar with load average display
- Temperature with colored indicator dot
- Backup status card with last run time, DB count, repo stats
- "Mentés most" button for manual backup trigger

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/handlers.go

@@ -35,7 +35,7 @@ func (s *Server) dashboardHandler(w http.ResponseWriter, _ *http.Request) {
 		}
 	}
 
-	sysInfo := system.GetInfo(s.cfg.Paths.HDDPath)
+	sysInfo := system.GetInfo(s.cfg.Paths.HDDPath, s.cpuCollector)
 
 	data := s.baseData("dashboard", "Vezérlőpult")
 	data["Stacks"] = stackList
@@ -44,6 +44,16 @@ func (s *Server) dashboardHandler(w http.ResponseWriter, _ *http.Request) {
 	data["TotalCount"] = len(stackList)
 	data["SystemInfo"] = sysInfo
 
+	// Backup status
+	data["BackupEnabled"] = s.cfg.Backup.Enabled
+	if s.backupMgr != nil {
+		dbDump, backupSt := s.backupMgr.GetStatus()
+		data["DBDumpStatus"] = dbDump
+		data["BackupStatus"] = backupSt
+		data["BackupRunning"] = s.backupMgr.IsRunning()
+		data["BackupMaxAgeHours"] = s.cfg.Monitoring.Thresholds.BackupMaxAgeHours
+	}
+
 	s.render(w, "dashboard", data)
 }