fix(cache): share:mac ZSET 添加 1h 兜底 TTL，防止永不调用 shareList 时 key 泄漏

- 新增 shareMacIndexTTL = 1h 常量
- Lua 脚本中原子执行 EXPIRE KEYS[3]
- 每次创建分享码续期 ZSET，活跃用户不受影响
- 无人调用 shareList 时 ZSET 1h 后自动过期清理

internal/cache/share_code_cache.go

@@ -9,7 +9,7 @@
 //	  expire_at               过期时间 (RFC3339)
 //	  persisted               是否已刷入 DB ("0"/"1")
 //
-//	share:mac:{mac}           ZSET — MAC 二级索引 (无 TTL, 查询时自动清理过期成员)
+//	share:mac:{mac}           ZSET, TTL 1h (兜底) — MAC 二级索引 (查询时主动清理过期成员)
 //	  member = share_code
 //	  score  = expire_at unix timestamp
 //
@@ -52,6 +52,7 @@ const (
 	shareMacIndexPrefix      = "share:mac:"
 	shareCodeLength          = 5
 	shareCodeTTL             = 30 * time.Minute
+	shareMacIndexTTL         = 1 * time.Hour
 	shareImportPendingTTL    = 12 * time.Hour
 	shareCodeCharset         = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"
 	shareCodeMaxRetries      = 20
@@ -78,6 +79,7 @@ redis.call('EXPIRE', KEYS[1], tonumber(ARGV[5]))
 redis.call('SADD', KEYS[2], ARGV[6])
 -- ZSET: score = expire_at unix timestamp, member = share code
 redis.call('ZADD', KEYS[3], tonumber(ARGV[7]), ARGV[6])
+redis.call('EXPIRE', KEYS[3], tonumber(ARGV[8]))
 return 1
 `)
 
@@ -123,7 +125,7 @@ func (c *ShareCodeCache) Create(ctx context.Context, macAddr, ipAddr string, eqD
 		key := shareCodeKey(code)
 		macIdxKey := shareMacIndexKey(macAddr)
 		ok, err := shareCreateScript.Run(ctx, c.rdb, []string{key, sharePendingSet, macIdxKey},
-			macAddr, ipAddr, eqJSON, expireAt.Format(time.RFC3339), int(shareCodeTTL.Seconds()), code, expireAt.Unix(),
+			macAddr, ipAddr, eqJSON, expireAt.Format(time.RFC3339), int(shareCodeTTL.Seconds()), code, expireAt.Unix(), int(shareMacIndexTTL.Seconds()),
 		).Int()
 		if err != nil {
 			return nil, fmt.Errorf("create share code in redis: %w", err)