Update README and rotate script to clarify container restart order and improve handling of additional restart containers

Dockers/gluetun-pia-wireguard-rotator/rotate.sh

@@ -41,14 +41,10 @@ pick_random_region() {
   printf '%s\n' "${regions[@]}" | shuf -n 1
 }
 
-parse_restart_containers() {
-  # CSV: "m3u-filter-vpn,m3u-editor,xtream-proxy" or JSON array.
-  # Falls back to GLUETUN_CONTAINER when unset.
+parse_additional_restart_containers() {
+  # Sidecars to restart after gluetun. CSV or JSON array.
   local raw="${RESTART_CONTAINERS:-}"
-  if [[ -z "$raw" ]]; then
-    echo "${GLUETUN_CONTAINER:-m3u-filter-vpn}"
-    return
-  fi
+  [[ -z "$raw" ]] && return 0
 
   if [[ "$raw" =~ ^\[.*\]$ ]]; then
     jq -r '.[]' <<<"$raw"
@@ -58,6 +54,23 @@ parse_restart_containers() {
   tr ',' '\n' <<<"$raw" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//' | awk 'NF'
 }
 
+parse_restart_containers() {
+  # Gluetun is always restarted first, then any RESTART_CONTAINERS (deduplicated).
+  local gluetun="${GLUETUN_CONTAINER:-m3u-filter-vpn}"
+  local -A seen=()
+  local container
+
+  echo "$gluetun"
+  seen["$gluetun"]=1
+
+  while IFS= read -r container; do
+    [[ -z "$container" ]] && continue
+    [[ -n "${seen[$container]+x}" ]] && continue
+    echo "$container"
+    seen["$container"]=1
+  done < <(parse_additional_restart_containers)
+}
+
 restart_containers() {
   local container restarted=()
   while IFS= read -r container; do