deploy: keep config backups out of dnsmasq conf dirs, cap at 10

Backups were written as <conf>.backup.<ts> next to the live file. Both
dnsmasq instances load every file in their conf dir (the host excludes
only .dpkg-*), so each backup was parsed as live config, resurrecting
removed domains and piling up one stale copy per deploy.

Write them to BACKUP_DIR (/var/backups/bbrkn) instead and keep the
newest BACKUP_KEEP (10) per file.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DR7zpSsdX28T4Kn6v4jPSS

scripts/deploy-to-gateway.sh

@@ -14,6 +14,11 @@ RESOLVE_CONF="${RESOLVE_CONF:-/tmp/92-resolve-bbrkn.conf}"
 NFTSET_TARGET_DIR="${NFTSET_TARGET_DIR:-/etc/dnsmasq.d}"
 RESOLVE_TARGET_DIR="${RESOLVE_TARGET_DIR:-${TARGET_DIR:-/opt/appdata/pihole/etc/dnsmasq.d}}"
 
+# Бэкапы — ВНЕ conf-dir: dnsmasq (и pihole) грузит из dnsmasq.d все файлы,
+# кроме исключённых расширений, так что *.backup.* там стал бы живым конфигом.
+BACKUP_DIR="${BACKUP_DIR:-/var/backups/bbrkn}"
+BACKUP_KEEP="${BACKUP_KEEP:-10}"   # сколько последних копий хранить на каждый файл
+
 DOCKER_CONTAINER="${DOCKER_CONTAINER:-pihole}"
 # systemd-сервис host-инстанса dnsmasq (:5350)
 HOST_DNSMASQ_SVC="${HOST_DNSMASQ_SVC:-dnsmasq}"
@@ -82,16 +87,31 @@ rollback() {
 # ==============================
 # Бэкап существующих файлов
 # ==============================
+# Оставляет BACKUP_KEEP самых свежих копий <name>.backup.<ts>
+# (ts вида YYYYmmdd-HHMMSS сортируется лексикографически).
+prune_backups() {  # <name>
+  local name="$1" old
+  find "$BACKUP_DIR" -maxdepth 1 -type f -name "${name}.backup.*" -printf '%f\n' \
+    | sort -r | tail -n +"$((BACKUP_KEEP + 1))" \
+    | while read -r old; do
+        rm -f -- "$BACKUP_DIR/$old"
+        echo "  pruned old backup $old"
+      done
+}
+
+mkdir -p "$BACKUP_DIR"
 ts=$(date +%Y%m%d-%H%M%S)
 if [ -f "$nftset_dest" ]; then
-  NFTSET_BACKUP="${nftset_dest}.backup.${ts}"
+  NFTSET_BACKUP="$BACKUP_DIR/${nftset_name}.backup.${ts}"
   cp "$nftset_dest" "$NFTSET_BACKUP"
   echo "Backed up $nftset_dest → $NFTSET_BACKUP"
+  prune_backups "$nftset_name"
 fi
 if [ -f "$resolve_dest" ]; then
-  RESOLVE_BACKUP="${resolve_dest}.backup.${ts}"
+  RESOLVE_BACKUP="$BACKUP_DIR/${resolve_name}.backup.${ts}"
   cp "$resolve_dest" "$RESOLVE_BACKUP"
   echo "Backed up $resolve_dest → $RESOLVE_BACKUP"
+  prune_backups "$resolve_name"
 fi
 
 # ==============================