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/backup/appdata.go

@@ -1,10 +1,12 @@
 package backup
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"os/exec"
 	"strings"
+	"time"
 
 	"gopkg.in/yaml.v3"
 )
@@ -76,8 +78,7 @@ func DiscoverAppData(provider StackDataProvider, backupPrefs map[string]bool, di
 			path := AppDataPath{HostPath: mount}
 			if fi, err := os.Stat(mount); err == nil && fi.IsDir() {
 				path.Exists = true
-				path.SizeBytes = appDirSizeBytes(mount)
-				path.SizeHuman = appDirSizeHuman(mount)
+				path.SizeBytes, path.SizeHuman = appDirSize(mount)
 			}
 			info.HDDPaths = append(info.HDDPaths, path)
 			info.HDDTotalSize += path.SizeBytes
@@ -131,34 +132,23 @@ func parseComposeNamedVolumes(composePath string) []AppDockerVolume {
 	return volumes
 }
 
-// appDirSizeHuman returns a human-readable size string for a directory using du.
-func appDirSizeHuman(path string) string {
-	cmd := exec.Command("du", "-sh", path)
+// appDirSize returns the total byte count and a human-readable string for a directory.
+// H2/H3: Single du invocation with 30s timeout replaces two separate calls.
+func appDirSize(path string) (int64, string) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, "du", "-sb", path)
 	output, err := cmd.Output()
 	if err != nil {
-		return "?"
+		return 0, "?"
 	}
 	fields := strings.Fields(string(output))
-	if len(fields) > 0 {
-		return fields[0]
+	if len(fields) == 0 {
+		return 0, "?"
 	}
-	return "?"
-}
-
-// appDirSizeBytes returns the total size in bytes for a directory.
-func appDirSizeBytes(path string) int64 {
-	cmd := exec.Command("du", "-sb", path)
-	output, err := cmd.Output()
-	if err != nil {
-		return 0
-	}
-	fields := strings.Fields(string(output))
-	if len(fields) > 0 {
-		var size int64
-		fmt.Sscanf(fields[0], "%d", &size)
-		return size
-	}
-	return 0
+	var size int64
+	fmt.Sscanf(fields[0], "%d", &size)
+	return size, humanizeBytes(size)
 }
 
 // humanizeBytes converts bytes to a human-readable string.