DDD workflow for spec-kit

[gabrielisback]

I created a DDD workflow by adding an extension and a preset, repo here: https://github.com/gabrielisback/spec-kit-ddd

As DDD requires overall architecture design for bounded contexts, this extension will create an overall arch document: ".specify/architecture.md". And then the set of original templates modified.

The DDD extension has two commands: "speckit.ddd.architecture" for creating mentioned overall architecture, and "speckit.ddd.model" for creating domain modal for one bounded context (one feature).

Anyone interested - very welcome to test it and give me feedback.