perf: Redis 操作优化，移除号池 key 列表的 Usage 聚合查询

- 号池 key 列表移除 Usage 表聚合查询(total_tokens/total_cost_usd)，消除慢 SQL
- cooldown 计数从 SCAN 改为 SCARD (O(1))，通过 cooldown_idx SET 维护索引
- 读路径 Lua 脚本移除 ZREMRANGEBYSCORE，清理移至写路径减少开销
- affinity 清理从 KEYS 改为 SCAN 分批删除，invalidate_all_for_provider 改用 pipeline 批量 MGET+UNLINK
- 缓存监控页添加清除按钮 loading 状态，Redis SCAN 并发限制为 4
- 提取 redis_utils 模块统一 SCAN+批量删除逻辑
- 调度热路径跳过 cooldown TTL 查询，account_state 预计算移出循环

tests/services/test_cache_affinity_manager.py

@@ -0,0 +1,131 @@
+import json
+from fnmatch import fnmatch
+
+import pytest
+
+from src.services.scheduling.affinity_manager import CacheAffinityManager
+
+
+class _FakeRedis:
+    def __init__(self, store: dict[str, str]):
+        self.store = dict(store)
+        self.keys_called = 0
+        self.scan_calls = 0
+        self.unlink_batches: list[tuple[str, ...]] = []
+        self.delete_batches: list[tuple[str, ...]] = []
+
+    async def scan(  # type: ignore[override]
+        self, cursor: int = 0, match: str | None = None, count: int = 10
+    ) -> tuple[int, list[str]]:
+        self.scan_calls += 1
+        pattern = match or "*"
+        matched = [key for key in sorted(self.store) if fnmatch(key, pattern)]
+        start = int(cursor)
+        batch = matched[start : start + count]
+        next_cursor = 0 if start + count >= len(matched) else start + count
+        return next_cursor, batch
+
+    async def get(self, key: str) -> str | None:
+        return self.store.get(key)
+
+    async def mget(self, keys: list[str]) -> list[str | None]:
+        return [self.store.get(k) for k in keys]
+
+    async def unlink(self, *keys: str) -> int:
+        self.unlink_batches.append(tuple(keys))
+        deleted = 0
+        for key in keys:
+            if key in self.store:
+                deleted += 1
+                self.store.pop(key, None)
+        return deleted
+
+    async def delete(self, *keys: str) -> int:
+        self.delete_batches.append(tuple(keys))
+        deleted = 0
+        for key in keys:
+            if key in self.store:
+                deleted += 1
+                self.store.pop(key, None)
+        return deleted
+
+    async def keys(self, _pattern: str) -> list[str]:
+        self.keys_called += 1
+        raise AssertionError("clear operations should not call Redis KEYS")
+
+
+@pytest.mark.asyncio
+async def test_clear_all_uses_scan_and_clears_l1_cache() -> None:
+    redis = _FakeRedis(
+        {
+            "cache_affinity:user-1:openai:model-a": json.dumps({"provider_id": "provider-a"}),
+            "cache_affinity:user-2:openai:model-b": json.dumps({"provider_id": "provider-b"}),
+            "cache_affinity:user-3:claude:model-c": json.dumps({"provider_id": "provider-c"}),
+            "other:key": json.dumps({"provider_id": "provider-x"}),
+        }
+    )
+    manager = CacheAffinityManager(redis_client=redis)
+
+    await manager._set_l1_entry(
+        "cache_affinity:user-1:openai:model-a", {"provider_id": "provider-a"}
+    )
+    await manager._set_l1_entry("other:key", {"provider_id": "provider-x"})
+
+    deleted_count = await manager.clear_all()
+
+    assert deleted_count == 3
+    assert redis.keys_called == 0
+    assert redis.scan_calls >= 1
+    assert redis.unlink_batches == [
+        (
+            "cache_affinity:user-1:openai:model-a",
+            "cache_affinity:user-2:openai:model-b",
+            "cache_affinity:user-3:claude:model-c",
+        )
+    ]
+    assert "other:key" in redis.store
+    assert all(not key.startswith("cache_affinity:") for key in redis.store)
+    assert await manager._get_l1_entry("cache_affinity:user-1:openai:model-a") is None
+    assert await manager._get_l1_entry("other:key") == {"provider_id": "provider-x"}
+
+
+@pytest.mark.asyncio
+async def test_invalidate_all_for_provider_uses_scan_not_keys() -> None:
+    redis = _FakeRedis(
+        {
+            "cache_affinity:user-1:openai:model-a": json.dumps({"provider_id": "provider-a"}),
+            "cache_affinity:user-2:openai:model-b": json.dumps({"provider_id": "provider-b"}),
+            "cache_affinity:user-3:claude:model-c": json.dumps({"provider_id": "provider-a"}),
+        }
+    )
+    manager = CacheAffinityManager(redis_client=redis)
+
+    await manager._set_l1_entry(
+        "cache_affinity:user-1:openai:model-a", {"provider_id": "provider-a"}
+    )
+    await manager._set_l1_entry(
+        "cache_affinity:user-2:openai:model-b", {"provider_id": "provider-b"}
+    )
+    await manager._set_l1_entry(
+        "cache_affinity:user-3:claude:model-c", {"provider_id": "provider-a"}
+    )
+
+    deleted_count = await manager.invalidate_all_for_provider("provider-a")
+
+    assert deleted_count == 2
+    assert redis.keys_called == 0
+    assert redis.scan_calls >= 1
+    # Pipeline path: batch MGET + batch UNLINK (not per-key DELETE).
+    assert len(redis.unlink_batches) == 1
+    assert set(redis.unlink_batches[0]) == {
+        "cache_affinity:user-1:openai:model-a",
+        "cache_affinity:user-3:claude:model-c",
+    }
+    assert redis.delete_batches == []
+    assert "cache_affinity:user-2:openai:model-b" in redis.store
+    assert "cache_affinity:user-1:openai:model-a" not in redis.store
+    assert "cache_affinity:user-3:claude:model-c" not in redis.store
+    assert await manager._get_l1_entry("cache_affinity:user-1:openai:model-a") is None
+    assert await manager._get_l1_entry("cache_affinity:user-2:openai:model-b") == {
+        "provider_id": "provider-b"
+    }