v0.12.4 — 15 bug fixes (CRITICAL/HIGH/MEDIUM)

CRITICAL:
- C1: SetAppBackupBulk data loss + nil map panic (settings.go)
- C2: UpdateStackConfig nil Env map panic (deploy.go)
- C3: ValidateDump missing scanner.Err() check (dbdump.go)

HIGH:
- H1: nextDailyRun DST bug — use time.Date(day+1) not Add(24h)
- H2: Cache Europe/Budapest timezone with sync.Once in scheduler
- H3: settings.save() leaks .tmp file on WriteFile failure
- H4: SetNotificationPrefs nil pointer panic
- H5: appDirSize + getDirSizeBytes ignore Sscanf return value
- H6: getDirSizeBytes has no timeout — add 30s context
- H7: dbdump.go tmpFile not using defer Close
- H8: UpdateCrossDriveStatus misleading comment

MEDIUM:
- M1: Replace custom containsBytes with strings.Contains
- M2: scheduler.Every() validates interval > 0
- M3: executeJob panic recovery now sets LastRun
- M4: logPostStartStatus copies env slice before goroutine
- M5: Cache timezone in web package via getTimezone() sync.Once

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

controller/internal/web/funcmap.go

@@ -4,18 +4,34 @@ import (
 	"fmt"
 	"html/template"
 	"strings"
+	"sync"
 	"time"
 
 	"gitea.dooplex.hu/admin/felhom-controller/internal/backup"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
 )
 
+var (
+	webTimezone     *time.Location
+	webTimezoneOnce sync.Once
+)
+
+// getTimezone returns the Europe/Budapest timezone, cached after first load.
+// Falls back to UTC if tzdata is unavailable.
+func getTimezone() *time.Location {
+	webTimezoneOnce.Do(func() {
+		loc, err := time.LoadLocation("Europe/Budapest")
+		if err != nil {
+			loc = time.UTC
+		}
+		webTimezone = loc
+	})
+	return webTimezone
+}
+
 // templateFuncMap returns the FuncMap used by all HTML templates.
 func (s *Server) templateFuncMap() template.FuncMap {
-	loc, err := time.LoadLocation("Europe/Budapest")
-	if err != nil {
-		loc = time.UTC
-	}
+	loc := getTimezone()
 
 	return template.FuncMap{
 		"stateColor": func(state stacks.ContainerState) string {

controller/internal/web/handlers.go

@@ -447,12 +447,7 @@ func (s *Server) backupsHandler(w http.ResponseWriter, r *http.Request) {
 			}
 			if cfg.LastRun != "" {
 				if t, err := time.Parse(time.RFC3339, cfg.LastRun); err == nil {
-					// M7: Handle LoadLocation error — fall back to UTC if tzdata missing.
-					loc, err := time.LoadLocation("Europe/Budapest")
-					if err != nil {
-						loc = time.UTC
-					}
-					item.LastRunShort = t.In(loc).Format("01-02 15:04")
+					item.LastRunShort = t.In(getTimezone()).Format("01-02 15:04")
 				}
 			}
 			fullStatus.CrossDriveSummary = append(fullStatus.CrossDriveSummary, item)
@@ -543,11 +538,7 @@ func (s *Server) buildAppBackupRows(
 	crossConfigs map[string]*settings.CrossDriveBackup,
 	destLabels map[string]string,
 ) []AppBackupRow {
-	// M7: Handle LoadLocation error — fall back to UTC if tzdata missing.
-	loc, err := time.LoadLocation("Europe/Budapest")
-	if err != nil {
-		loc = time.UTC
-	}
+	loc := getTimezone()
 
 	// Build a quick lookup: which stacks have a DB dump?
 	dbStacks := make(map[string]bool)