Add a skill for AI agents, so they can use Drupal Flake effectively

Problem/Motivation

When using a coding agent like Claude Code or Opencode for development on Drupal sites, they don't often provide good context to help with testing or development. Creating a "Skill" for Drupal Flake can help AI agents understand how to start/stop the environment, detect what is running, and assist with setting up test environments or new site installations.

These agents search the project code for a SKILLS.md in particular directories, and if found, can automatically load them to provide better assistance with your project.

Steps to reproduce

Proposed resolution

For an initial skill, I'm creating a skill that first of all determines whether your current environment is active, configured to use Drupal Flake or DDev or a Docker runtime environment, and provide some context so you don't need to keep telling it how to use drush or load from the right domain.

I'm also building in context to help install Drupal from scratch, to support installing from different sources -- right now, Drupal CMS 2.0, Commerce Kickstart, or vanilla Drupal core.

Remaining tasks

User interface changes

API changes

Data model changes