fix(release): publish monthly backup marker after successful copy

deploy/deploy.sh

@@ -525,12 +525,14 @@ apply_backup_retention() {
     return 1
   fi
 
-  local month monthly_root monthly_dir
+  local month monthly_root monthly_dir complete_tmp
   month="$(TZ="$timezone" date +%Y-%m)"
   monthly_root="$BACKUP_DIR/monthly"
   monthly_dir="$monthly_root/$month"
-  mkdir -p "$monthly_root"
-  chmod 700 "$monthly_root"
+  if ! mkdir -p "$monthly_root" || ! chmod 700 "$monthly_root"; then
+    echo "Could not prepare monthly backup directory. Aborting deploy."
+    return 1
+  fi
 
   local current_files=("$BACKUP_DIR"/jobtracker-*"-$BACKUP_STAMP".*)
   if [ ! -e "${current_files[0]}" ]; then
@@ -539,11 +541,21 @@ apply_backup_retention() {
   fi
 
   if [ ! -f "$monthly_dir/.complete" ]; then
-    mkdir -p "$monthly_dir"
-    chmod 700 "$monthly_dir"
-    cp --preserve=mode,timestamps -- "${current_files[@]}" "$monthly_dir/"
-    printf '%s\n' "$BACKUP_STAMP" > "$monthly_dir/.complete"
-    chmod 600 "$monthly_dir/.complete"
+    if ! mkdir -p "$monthly_dir" || ! chmod 700 "$monthly_dir" ||
+        ! cp --preserve=mode,timestamps -- "${current_files[@]}" "$monthly_dir/"; then
+      echo "Could not retain monthly recovery files. Aborting deploy."
+      return 1
+    fi
+    if ! complete_tmp="$(mktemp "$monthly_dir/.complete.XXXXXX")"; then
+      echo "Could not create monthly recovery marker. Aborting deploy."
+      return 1
+    fi
+    if ! printf '%s\n' "$BACKUP_STAMP" > "$complete_tmp" ||
+        ! mv -T -- "$complete_tmp" "$monthly_dir/.complete"; then
+      rm -f -- "$complete_tmp"
+      echo "Could not publish monthly recovery marker. Aborting deploy."
+      return 1
+    fi
     echo "Monthly recovery set retained: ${monthly_dir}"
   fi