v0.4.5: Add dedicated Backup page (Biztonsági mentés)

New /backups page with full backup system visibility:
- Status overview cards (local/remote backup, DB count, repo size)
- Schedule section with next-run times and retention policy
- Database table with type, size, validation (table count), status
- Snapshot history table with per-snapshot stats
- Repository info card with paths, integrity status, remote placeholder
- "Mentés most" button with auto-refresh polling
- Empty state when backup not configured

Backend: SnapshotRecord history (ring buffer), DumpValidation,
ListDumpFiles, ListSnapshots, GetFullStatus, restic check tracking.
Server accepts scheduler for next-run time calculation.

Sidebar nav updated with 3rd item, dashboard backup card title clickable.

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

controller/internal/web/funcmap.go

@@ -3,7 +3,10 @@ package web
 import (
 	"fmt"
 	"html/template"
+	"strings"
+	"time"
 
+	"gitea.dooplex.hu/admin/felhom-controller/internal/backup"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
 )
 
@@ -157,5 +160,145 @@ func (s *Server) templateFuncMap() template.FuncMap {
 				return "available"
 			}
 		},
+		"timeAgo": func(t time.Time) string {
+			if t.IsZero() {
+				return "–"
+			}
+			loc, _ := time.LoadLocation("Europe/Budapest")
+			if loc == nil {
+				loc = time.UTC
+			}
+			now := time.Now().In(loc)
+			d := now.Sub(t.In(loc))
+			switch {
+			case d < time.Minute:
+				return "most"
+			case d < time.Hour:
+				return fmt.Sprintf("%d perce", int(d.Minutes()))
+			case d < 24*time.Hour:
+				return fmt.Sprintf("%d órája", int(d.Hours()))
+			case d < 48*time.Hour:
+				return "tegnap"
+			default:
+				return fmt.Sprintf("%d napja", int(d.Hours()/24))
+			}
+		},
+		"fmtTime": func(t time.Time) string {
+			if t.IsZero() {
+				return "–"
+			}
+			loc, _ := time.LoadLocation("Europe/Budapest")
+			if loc == nil {
+				loc = time.UTC
+			}
+			return t.In(loc).Format("2006-01-02 15:04")
+		},
+		"fmtTimeShort": func(t time.Time) string {
+			if t.IsZero() {
+				return "–"
+			}
+			loc, _ := time.LoadLocation("Europe/Budapest")
+			if loc == nil {
+				loc = time.UTC
+			}
+			lt := t.In(loc)
+			now := time.Now().In(loc)
+			if lt.Year() == now.Year() && lt.YearDay() == now.YearDay() {
+				return lt.Format("15:04")
+			}
+			return lt.Format("01-02 15:04")
+		},
+		"dbTypeLabel": func(t backup.DBType) string {
+			switch t {
+			case backup.DBTypePostgres:
+				return "PostgreSQL"
+			case backup.DBTypeMariaDB:
+				return "MariaDB"
+			default:
+				return string(t)
+			}
+		},
+		"nextRunLabel": func(t time.Time) string {
+			if t.IsZero() {
+				return "–"
+			}
+			loc, _ := time.LoadLocation("Europe/Budapest")
+			if loc == nil {
+				loc = time.UTC
+			}
+			lt := t.In(loc)
+			now := time.Now().In(loc)
+			timeStr := lt.Format("15:04")
+			if lt.Year() == now.Year() && lt.YearDay() == now.YearDay() {
+				return "ma " + timeStr
+			}
+			if lt.Year() == now.Year() && lt.YearDay() == now.YearDay()+1 {
+				return "holnap " + timeStr
+			}
+			return lt.Format("2006-01-02") + " " + timeStr
+		},
+		"pruneLabel": func(s string) string {
+			switch strings.ToLower(s) {
+			case "weekly":
+				return "vasárnap"
+			case "daily":
+				return "naponta"
+			case "sunday":
+				return "vasárnap"
+			default:
+				return s
+			}
+		},
+		"nextPruneLabel": func(schedule string) string {
+			loc, _ := time.LoadLocation("Europe/Budapest")
+			if loc == nil {
+				loc = time.UTC
+			}
+			now := time.Now().In(loc)
+			var next time.Time
+			switch strings.ToLower(schedule) {
+			case "daily":
+				next = now.Add(24 * time.Hour)
+			default: // weekly/sunday
+				daysUntilSunday := (7 - int(now.Weekday())) % 7
+				if daysUntilSunday == 0 && now.Hour() >= 4 {
+					daysUntilSunday = 7
+				}
+				next = now.AddDate(0, 0, daysUntilSunday)
+			}
+			return next.Format("2006-01-02")
+		},
+		"fmtDuration": func(d time.Duration) string {
+			if d < time.Second {
+				return "< 1s"
+			}
+			if d < time.Minute {
+				return fmt.Sprintf("%ds", int(d.Seconds()))
+			}
+			return fmt.Sprintf("%dm %ds", int(d.Minutes()), int(d.Seconds())%60)
+		},
+		"fmtBytes": func(b int64) string {
+			const (
+				kb = 1024
+				mb = 1024 * kb
+				gb = 1024 * mb
+			)
+			switch {
+			case b >= int64(gb):
+				return fmt.Sprintf("%.1f GB", float64(b)/float64(gb))
+			case b >= int64(mb):
+				return fmt.Sprintf("%.1f MB", float64(b)/float64(mb))
+			case b >= int64(kb):
+				return fmt.Sprintf("%.1f KB", float64(b)/float64(kb))
+			default:
+				return fmt.Sprintf("%d B", b)
+			}
+		},
+		"shortID": func(id string) string {
+			if len(id) > 8 {
+				return id[:8]
+			}
+			return id
+		},
 	}
 }