Fix multi-recovery metadata indexing and add regression coverage.

[hongzhi-gao]

中文

TSMIterator 内部用来聚合设备元数据的 map，键是 std::shared_ptr，但没有使用按设备值比较的 comparator，默认按指针地址比较。
结果就是：同一个逻辑设备（比如 d1）如果来自不同恢复轮次、指针不同，会被当成不同 key。
在 TSMIterator 的设备聚合 map 上使用 IDeviceIDComparator，让 key 比较按设备内容而不是指针地址。

English

Inside TSMIterator, the map used to aggregate device metadata uses std::shared_ptr<IDeviceID> as the key, but it does not use a value-based comparator for devices; by default, it compares pointer addresses.

As a result, the same logical device (for example, d1) coming from different recovery rounds can have different pointer instances and be treated as different keys.

The fix is to use IDeviceIDComparator for the device-aggregation map in TSMIterator, so keys are compared by device identity/content instead of pointer address.