Switch documentation from `mkdocs-material` to `zensical`

Nobody has claimed this yet.

### Feature request

For ease of document deployment as well as new functionality, it might make sense to switch over to [zensical](https://github.com/zensical/zensical).

### Motivation

The current documentation engine is [`mkdocs-material`](https://github.com/squidfunk/mkdocs-material) which is an amazing framework to easily built and create documentation. However, it is going into [maintenance mode](https://github.com/squidfunk/mkdocs-material/issues/8523). Instead, they are going to develop a new framework over which they have more control, namely [zensical](https://github.com/zensical/zensical). Looking at their [announcement](https://squidfunk.github.io/mkdocs-material/blog/2025/11/05/zensical/) it seems that it is worthwile to consider this new framework, especially since I have been a major fan of what they created before so I'm curious to see what they do next.

### Your contribution

I can start porting this over but haven't found the time to explore this new engine. First, let's check how big of a port it will be and how much functionality will remain the same (along with paths which really should remain the same).

No files or tests are named. Start by reviewing the repository's current mkdocs-material configuration and comparing it with zensical's migration requirements. The work is done when documentation deployment, existing paths, and currently used functionality remain working after the engine switch.

Written by the indexing model from the issue text.