Improvements for v1.0.0-rc.1

[loranallensmith]

This is admittedly a massive PR, but I'm opening it here for posterity given that these updates were largely written with the help of AI code-gen tools. If things go sideways in the future, this PR would likely be a great starting point for bisecting changes to see where problems were introduced.

About these changes:

Whereas v0.1.0 represents a minimal proof of concept, this 1.0.0 version aims to implement all of the core functionality for initializing, cloning, generating, validating, planning, and applying changes to a Compose project. See the CHANGELOG and the included docs/ files for more info about how the tool behaves and typical workflows.

These changes also include tests for any functionality that was introduced. The AI-assisted workflow I used for them incorporated test-driven development, so any changes had tests that were required to pass before they could be committed.

Next steps

• Before officially bumping to v.1.0.0, I'd like to try this out internally for a while. I suspect we may want to make changes to the "shape" of the local repository since it's such a critical piece of the puzzle.
• Once we've nailed down the architecture of a compose repo and ensured that all of the commands can consistently synchronize changes between local machines and live Compose projects, we may be ready to share this with more folks.