v0.12.3 — Security & correctness bug fixes (33 bugs)

CRITICAL: 10 data race and security fixes — backup.go mutex coverage
(C1-C4), IsSystemDisk 12-bit major/minor (C5), /dev/ path validation
(C6), extractName traversal (C7), TargetPath/DestinationPath against
registered paths (C8-C9), ParseComposeHDDMounts Clean-before-prefix (C10).

HIGH: 17 logic/resource fixes — ValidateDump bufio.Scanner (H1), single
appDirSize() with 30s timeout (H2/H3), snapshot ID regex (H4), cross-drive
restic prune (H5), temp file order (H6), dirSizeBytes errors (H7), atomic
fstab (H8), IsDeviceMounted suffix check (H9), eMMC partition mapping (H10),
bytesCopied mutex (H11), separator-aware migrate prefix (H13), DeleteStack
error on compose-down (H14), docker 60s timeout (H16), NotificationPrefs
deep-copy (H17), wipefs warning (H18), fstab rollback on mount fail (H19).

MEDIUM: 7 code quality fixes — formatBytes dedup (M1), .tmp filter order
(M2), sizeBytes string type (M3), elapsed in message (M6), LoadLocation
fallback (M7), pathCovers separator (M10), cancelEditLabel textContent (M11).

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

controller/internal/web/handlers.go

@@ -1,6 +1,7 @@
 package web
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -446,7 +447,11 @@ func (s *Server) backupsHandler(w http.ResponseWriter, r *http.Request) {
 			}
 			if cfg.LastRun != "" {
 				if t, err := time.Parse(time.RFC3339, cfg.LastRun); err == nil {
-					loc, _ := time.LoadLocation("Europe/Budapest")
+					// 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")
 				}
 			}
@@ -538,7 +543,11 @@ func (s *Server) buildAppBackupRows(
 	crossConfigs map[string]*settings.CrossDriveBackup,
 	destLabels map[string]string,
 ) []AppBackupRow {
-	loc, _ := time.LoadLocation("Europe/Budapest")
+	// M7: Handle LoadLocation error — fall back to UTC if tzdata missing.
+	loc, err := time.LoadLocation("Europe/Budapest")
+	if err != nil {
+		loc = time.UTC
+	}
 
 	// Build a quick lookup: which stacks have a DB dump?
 	dbStacks := make(map[string]bool)
@@ -1243,8 +1252,10 @@ func (s *Server) syncFileBrowserMounts() {
 		return
 	}
 
-	// Recreate container
-	cmd := exec.Command("docker", "compose", "up", "-d", "--remove-orphans")
+	// Recreate container — H16: use 60s timeout to prevent hanging indefinitely.
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, "docker", "compose", "up", "-d", "--remove-orphans")
 	cmd.Dir = filepath.Dir(composePath)
 	if out, err := cmd.CombinedOutput(); err != nil {
 		s.logger.Printf("[ERROR] Failed to recreate FileBrowser: %s — %v", string(out), err)