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/funcmap.go

@@ -129,5 +129,20 @@ func (s *Server) templateFuncMap() template.FuncMap {
 			}
 			return result
 		},
+		"tempColor": func(celsius float64) string {
+			if celsius > 75 {
+				return "red"
+			}
+			if celsius >= 60 {
+				return "yellow"
+			}
+			return "green"
+		},
+		"fmtTemp": func(celsius float64) string {
+			return fmt.Sprintf("%.0f°C", celsius)
+		},
+		"fmtLoad": func(load float64) string {
+			return fmt.Sprintf("%.2f", load)
+		},
 	}
 }