Updating spec-kit for an ongoing project

[ferBo]

I've been using spec-kit for a new project and am loving it so far. The ability to define my project’s rules using constitution.md and then propagate changes with the /constitution command has been incredibly helpful.

As spec-kit is constantly evolving, I'm anticipating the need to update it in the future to take advantage of new features and fixes. However, there is currently no official update command or process, and I'm concerned about what would happen if a future update overwrites my carefully crafted constitution.md file, as well as the constitution-aligned templates.

To make spec-kit easier and safer to use on long-term projects, I would like to propose a new command: specify update.

This command would handle updates in a "non-destructive" manner. It would install the latest version of spec-kit but would not overwrite the user's existing constitution.md file, while updating current templates to the new version's standards.

A safe update process would be a huge value-add for the community. It would encourage users to keep their projects up-to-date without the fear of breaking their core configurations, which would lead to wider adoption and a more positive user experience.

[ferBo]

Whoops, I see that #168 already prompted for this.