Tagging mechanism for WSL distributions

**Summary**
Introduce a tagging mechanism for WSL distributions using a new property in the `wsl-distribution.conf` configuration file. The tag should be exposed to plugins via the `WSLDistributionInformation` and `WslOfflineDistributionInformation` structures to enable advanced filtering, categorization, and functionality based on the distribution's tag.

**Motivation**
Plugins often require additional context about WSL distributions to provide customized behavior. A tagging system would:

- Allow developers and administrators to annotate distributions with meaningful metadata.
- Enable plugins to filter or take action based on the tag.
- Improve the scalability and manageability of large or diverse WSL environments.

Start by locating the wsl-distribution.conf parsing and the WSLDistributionInformation and WslOfflineDistributionInformation structures. Trace how distribution metadata reaches plugins, then define the tag's configuration and exposure path; done means both structures provide the configured tag for plugin filtering and categorization.

Written by the indexing model from the issue text.