fix(provision): harden batch scoping and remote43 import validation

scripts/host_access_prep_lib.sh

@@ -34,6 +34,24 @@ WHERE key = $(sql_literal "$api_key");
 SQL
 }
 
+build_api_key_auth_cache_key() {
+  local api_key="$1"
+  local digest
+  digest="$(printf '%s' "$api_key" | sha256sum | awk '{print $1}')"
+  printf 'apikey:auth:%s' "$digest"
+}
+
+build_user_balance_cache_key() {
+  local user_id="$1"
+  printf 'billing:balance:%s' "$user_id"
+}
+
+build_subscription_billing_cache_key() {
+  local user_id="$1"
+  local group_id="$2"
+  printf 'billing:sub:%s:%s' "$user_id" "$group_id"
+}
+
 build_upsert_subscription_sql() {
   local user_id="$1"
   local group_id="$2"