fix: reject REDIS_CACHE_TTL<=0 (kill implicit never-expire)

app/harness/video_split_cli.py

@@ -248,13 +248,15 @@ def _build_redis_cache(settings: Any) -> Any | None:
     """按 .env redis_url 构建响应缓存（不可用则降级 None，与 main 一致）。"""
     if not settings.redis_url:
         return None
+
+    from adapters.redis_cache import RedisResponseCache, _resolve_cache_ttl
+
+    # 配置校验 fail-loud（不属于 Redis 连接故障，不得被下方降级 except 吞掉）
+    ttl_s = _resolve_cache_ttl(settings.redis_cache_ttl)
     try:
         import redis.asyncio as aioredis
 
-        from adapters.redis_cache import RedisResponseCache
-
         redis_client = aioredis.from_url(settings.redis_url, decode_responses=True)
-        ttl_s = settings.redis_cache_ttl if settings.redis_cache_ttl > 0 else None
         return RedisResponseCache(redis=redis_client, ttl_s=ttl_s)
     except Exception:
         logger.warning("Redis 缓存不可用，诊断降级为无缓存模式")