Add persistent partner conf backup across reboots

conf_cache_save.sh runs first on array stop — snapshots partner confs from RAM
cache to /boot/config/varaverk/conf_bak/ before anything else shuts down.

conf_cache_restore.sh runs after conf_sync.sh on array start — if partner was
unreachable and RAM cache is incomplete, loads the backup into RAM then removes
it. Normal reboots: backup written, fresh pull succeeds, backup deleted unused.
Edge case (partner down at boot): backup fills the gap so fallback.sh has the
partner vars it needs to operate correctly.

System_Essentials/conf_cache_save.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+# ==============================================================================================
+# ============================= Conf Cache Save ================================================
+# ==============================================================================================
+#
+# PURPOSE
+# ─────────────────────────────────────────────────────────────────────────────
+# Snapshots the partner conf RAM cache to /boot/config/varaverk/conf_bak/ on
+# array stop. Survives reboot. Used by conf_cache_restore.sh at next array start
+# to reload partner vars into RAM when the partner is unreachable at boot time.
+#
+# Runs as the first step in ARRAY_STOP_SCRIPTS — while the RAM cache is fresh
+# and before anything else changes. If partner is reachable at next start,
+# conf_sync.sh gets a fresh copy and the backup is never used. If partner is
+# down, the backup fills the gap so fallback.sh has the vars it needs.
+#
+# Only partner confs are saved — own conf is always on disk.
+# Location is outside the git repo and outside the main plugin folder.
+# ==============================================================================================
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/../load_config.sh"
+
+parse_args "$@"
+detect_hosts
+
+RAM_CACHE="/tmp/.vv/config/cached/.confs"
+SAVE_DIR="/boot/config/varaverk/conf_bak"
+
+[[ "$DRY_RUN" == true ]] && warn "DRY RUN — no files will be written"
+
+if [[ ! -d "$RAM_CACHE" ]]; then
+    log "No RAM conf cache found — nothing to save"
+    exit 0
+fi
+
+saved=0
+for conf in "$RAM_CACHE"/host*.conf; do
+    [[ -f "$conf" ]] || continue
+    base="$(basename "$conf")"
+    [[ "${base,,}" == "${MY_ID,,}.conf" ]] && continue
+
+    if [[ "$DRY_RUN" == true ]]; then
+        warn "DRY RUN — would save $base → $SAVE_DIR/"
+        (( saved++ ))
+        continue
+    fi
+
+    mkdir -p "$SAVE_DIR"
+    if cp "$conf" "$SAVE_DIR/$base"; then
+        echo "Saved $base → $SAVE_DIR ✅"
+        (( saved++ ))
+    else
+        warn "Failed to save $base"
+    fi
+done
+
+if [[ "$saved" -eq 0 ]]; then
+    log "No partner confs in RAM cache — nothing saved"
+else
+    echo "Conf cache saved: $saved partner conf(s) → $SAVE_DIR"
+fi