fix: get or create cached full customer overwrites previous cache on set

server/src/_luaScriptsV2/luaScriptsV2.ts

@@ -76,6 +76,15 @@ export const DELETE_FULL_CUSTOMER_CACHE_SCRIPT = readFileSync(
 	"utf-8",
 );
 
+/**
+ * Lua script for setting a FullCustomer cache in Redis.
+ * Checks stale-write guard, checks if cache exists, and sets cache atomically.
+ */
+export const SET_FULL_CUSTOMER_CACHE_SCRIPT = readFileSync(
+	join(DELETE_CACHE_DIR, "setFullCustomerCache.lua"),
+	"utf-8",
+);
+
 /**
  * Lua script for batch deleting multiple FullCustomer caches from Redis.
  * For each customer: checks test guard, sets stale-write guard, deletes cache.