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/cache.go

@@ -8,6 +8,8 @@ import (
 	"math/rand"
 	"sync"
 	"time"
+
+	"github.com/redis/go-redis/v9"
 )
 
 var ErrKeyNotFound = errors.New("key not found")
@@ -52,6 +54,10 @@ type Cache interface {
 	ZRangeByScore(ctx context.Context, key string, min, max string, offset, count int64) ([]string, error)
 	// ZRevRangeByScore 按分数范围获取成员（降序）
 	ZRevRangeByScore(ctx context.Context, key string, max, min string, offset, count int64) ([]string, error)
+	// ZRevRange 按排名倒序取成员（score 从高到低，start/stop 为排名下标，含端点）
+	ZRevRange(ctx context.Context, key string, start, stop int64) ([]string, error)
+	// ZReplaceSortedSet 原子替换整个 ZSET（先删后批量写入）
+	ZReplaceSortedSet(ctx context.Context, key string, members []redis.Z) error
 	// ZRem 删除 Sorted Set 成员
 	ZRem(ctx context.Context, key string, members ...interface{}) error
 	// ZCard 获取 Sorted Set 成员数量
@@ -130,6 +136,11 @@ func normalizeKey(key string) string {
 	return cmp.Or(settings.KeyPrefix, "") + ":" + key
 }
 
+// ResolveKey 返回带全局前缀的实际 Redis 键（供需直连 Redis 的组件使用）
+func ResolveKey(key string) string {
+	return normalizeKey(key)
+}
+
 func normalizePrefix(prefix string) string {
 	return cmp.Or(settings.KeyPrefix, "") + ":" + prefix
 }

internal/cache/keys.go

@@ -9,6 +9,10 @@ const (
 	// 帖子相关
 	PrefixPostList = "posts:list"
 	PrefixPost     = "posts:detail"
+	// HotRankZSet 热门榜（有序集合，member=post_id，score=归一化热度，仅存 TopN）
+	HotRankZSet = "posts:hot:zset"
+	// HotRankTopIDs 热门榜有序 post_id 列表（JSON []string，供分层缓存本地层命中）
+	HotRankTopIDs = "posts:hot:top_ids"
 
 	// 会话相关
 	PrefixConversationList   = "conversations:list"
@@ -36,10 +40,20 @@ const (
 )
 
 // PostListKey 生成帖子列表缓存键
-// postType: 帖子类型 (recommend, hot, follow, latest)
+// postType: 帖子类型 (hot, follow, latest)
 // page: 页码
 // pageSize: 每页数量
 // userID: 用户维度（仅在个性化列表如 follow 场景使用）
+// HotRankZSetKey 热门榜 Redis ZSET 逻辑键（仅存 TopN，会经 normalizeKey 加前缀）
+func HotRankZSetKey() string {
+	return HotRankZSet
+}
+
+// HotRankTopIDsKey 热门榜 Top 顺序 ID 列表键（会经 normalizeKey 加前缀）
+func HotRankTopIDsKey() string {
+	return HotRankTopIDs
+}
+
 func PostListKey(postType string, userID string, page, pageSize int) string {
 	if userID == "" {
 		return fmt.Sprintf("%s:%s:%d:%d", PrefixPostList, postType, page, pageSize)

internal/cache/layered_cache.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	redislib "github.com/redis/go-redis/v9"
 	"go.uber.org/zap"
 
 	redisPkg "carrot_bbs/internal/pkg/redis"
@@ -294,6 +295,21 @@ func (c *LayeredCache) ZRevRangeByScore(ctx context.Context, key string, max, mi
 	return c.redis.ZRevRangeByScore(ctx, key, max, min, offset, count)
 }
 
+func (c *LayeredCache) ZRevRange(ctx context.Context, key string, start, stop int64) ([]string, error) {
+	if !c.enabled || c.redis == nil {
+		return nil, ErrKeyNotFound
+	}
+	return c.redis.ZRevRange(ctx, key, start, stop)
+}
+
+func (c *LayeredCache) ZReplaceSortedSet(ctx context.Context, key string, members []redislib.Z) error {
+	if !c.enabled || c.redis == nil {
+		return ErrKeyNotFound
+	}
+	c.local.Delete(key)
+	return c.redis.ZReplaceSortedSet(ctx, key, members)
+}
+
 func (c *LayeredCache) ZRem(ctx context.Context, key string, members ...any) error {
 	if !c.enabled || c.redis == nil {
 		return nil

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)