fix: inverted tag expiration in Redis handler + saveItemOptions board name

- Fix critical bug: tag expiration comparison was inverted (< should be >)
  in Redis cache handler, which would prevent revalidateTag from clearing
  stale entries
- Pass board name to invalidateBoardCache in saveItemOptions
- Add clarifying comment about two-tier invalidation helpers

packages/next-cache-handler/src/redis-handler.ts

@@ -57,7 +57,7 @@ export class RedisCacheHandler implements CacheHandler {
 
       const allTags = [...parsed.tags, ...softTags];
       const expiration = await this.getExpiration(allTags);
-      if (expiration !== 0 && expiration < parsed.timestamp) {
+      if (expiration !== 0 && expiration > parsed.timestamp) {
         return undefined;
       }