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_restore.sh

@@ -0,0 +1,77 @@
+#!/bin/bash
+# ==============================================================================================
+# ============================= Conf Cache Restore =============================================
+# ==============================================================================================
+#
+# PURPOSE
+# ─────────────────────────────────────────────────────────────────────────────
+# Runs at array start after conf_sync.sh. Checks whether partner confs made it
+# into the RAM cache. If any are missing (partner was unreachable at boot) and
+# a persistent backup exists from the previous shutdown, loads the missing confs
+# from backup into the RAM cache so scripts like fallback.sh have partner vars.
+#
+# Always removes the persistent backup when done — used or not.
+#
+# Normal reboot (partner up):
+#   conf_sync.sh pulls fresh → RAM cache complete → backup not needed → removed
+#
+# Edge case (partner down at boot):
+#   conf_sync.sh fails to pull → RAM cache missing partner → backup loaded into
+#   RAM → backup removed → fallback.sh runs with last-known-good partner vars
+#
+# Own conf is never in the backup — it's always on disk.
+# ==============================================================================================
+
+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 changes will be made"
+
+if [[ ! -d "$SAVE_DIR" ]]; then
+    log "No persistent conf backup found — nothing to restore"
+    exit 0
+fi
+
+restored=0
+for conf in "$SAVE_DIR"/host*.conf; do
+    [[ -f "$conf" ]] || continue
+    base="$(basename "$conf")"
+    [[ "${base,,}" == "${MY_ID,,}.conf" ]] && continue
+
+    if [[ -f "$RAM_CACHE/$base" ]]; then
+        log "$base already in RAM cache (conf_sync succeeded) — skipping"
+        continue
+    fi
+
+    if [[ "$DRY_RUN" == true ]]; then
+        warn "DRY RUN — would restore $base → RAM cache"
+        (( restored++ ))
+        continue
+    fi
+
+    mkdir -p "$RAM_CACHE"
+    if cp "$conf" "$RAM_CACHE/$base"; then
+        echo "Restored $base from persistent backup → RAM cache ✅"
+        (( restored++ ))
+    else
+        warn "Failed to restore $base"
+    fi
+done
+
+[[ "$restored" -gt 0 ]] && \
+    warn "Loaded $restored partner conf(s) from persistent backup — partner was unreachable at array start"
+
+if [[ "$DRY_RUN" == false ]]; then
+    rm -rf "$SAVE_DIR"
+    log "Persistent conf backup cleared"
+else
+    warn "DRY RUN — would remove $SAVE_DIR"
+fi
+
+exit 0