Tailwind upgrade and extra goodies

[anchovie91471]

I've got a forked version of Slayed that I've upgraded to Tailwind 4, updated some of the dependencies to newest versions & added styling to account pages (they are unstyled presently in this repo).

I also added Schematic and switched all the templates in Slayed to use it (instead of hardcoded JSON schema). I recently took over maintenance of this repo. It saves a ton of time managing schema for sections, blocks, locales & settings by generating the schema from a set of Javascript files and keeps things consistent by defining the schema in a single location, making it reusable.

I was wondering if there was any interest in merging these changes. If so, I'd be happy to open a PR. Here's the forked repo: https://github.com/anchovie91471/slayed