documentation: #3623776 Add AGENTS.md and CLAUDE.md
Adds AGENTS.md with the working rules of this project, and CLAUDE.md pointing at it.
The notes cover the DDEV workflow, how recipes install config, the hook and code style, the issue and merge request conventions, and the release steps.
AI-Generated: Yes
Checkpoints
- Issue created with a clear summary
- Merge request opened
- CI pipeline passes