refactor: remove Gorse integration and implement HotRank feature

- Removed Gorse-related configurations, handlers, and dependencies from the codebase.
- Introduced HotRank feature with configuration options for ranking posts based on recent activity.
- Updated application structure to support HotRank processing, including new caching mechanisms and database interactions.
- Cleaned up related DTOs and repository methods to reflect the removal of Gorse and the addition of HotRank functionality.

internal/cache/redis_cache.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"time"
 
-	"github.com/redis/go-redis/v9"
+	redislib "github.com/redis/go-redis/v9"
 	"go.uber.org/zap"
 
 	redisPkg "carrot_bbs/internal/pkg/redis"
@@ -53,7 +53,7 @@ func (c *RedisCache) Get(key string) (interface{}, bool) {
 	key = normalizeKey(key)
 	data, err := c.client.Get(c.ctx, key)
 	if err != nil {
-		if err == redis.Nil {
+		if err == redislib.Nil {
 			return nil, false
 		}
 		zap.L().Error("Failed to get key",
@@ -219,6 +219,25 @@ func (c *RedisCache) ZRevRangeByScore(ctx context.Context, key string, max, min
 	return c.client.ZRevRangeByScore(ctx, key, max, min, offset, count)
 }
 
+// ZRevRange 按排名倒序获取成员
+func (c *RedisCache) ZRevRange(ctx context.Context, key string, start, stop int64) ([]string, error) {
+	key = normalizeKey(key)
+	return c.client.ZRevRange(ctx, key, start, stop)
+}
+
+// ZReplaceSortedSet 删除后整表重写 ZSET
+func (c *RedisCache) ZReplaceSortedSet(ctx context.Context, key string, members []redislib.Z) error {
+	key = normalizeKey(key)
+	rdb := c.client.GetClient()
+	if err := rdb.Del(ctx, key).Err(); err != nil {
+		return err
+	}
+	if len(members) == 0 {
+		return nil
+	}
+	return c.client.ZAddArgs(ctx, key, members...)
+}
+
 // ZRem 删除 Sorted Set 成员
 func (c *RedisCache) ZRem(ctx context.Context, key string, members ...interface{}) error {
 	key = normalizeKey(key)