N813 seems too broad in scope

Hi, currently N813 is raised even for cases such as
``` python
import netCDF4 as nc
```
which seem innocuous from the point of view of the rule: https://docs.astral.sh/ruff/rules/camelcase-imported-as-lowercase/

Would it make sense to restrict the applicability of this rule to cases where `name.to_lowercase() == asname.to_lowercase()`? I would be happy to send a PR if that was the case!

Start with the N813 implementation and reproduce the reported `import netCDF4 as nc` example against the rule described in the linked documentation. Confirm the intended cases still produce diagnostics while this innocuous import does not; add or update coverage for both outcomes.

Written by the indexing model from the issue text.