Add `CLAUDE.md`

[donyunardi]

Description

Add a CLAUDE.md file to this repository to provide repository-specific context and guidance when working with Claude Code.

The structure and expected content for CLAUDE.md are being defined in insightsengineering/nestdevs-tasks#121. The implementation should follow the agreed structure from that issue and adapt the content to this repository.

The CLAUDE.md should capture the relevant repository-specific information while following the common conventions agreed for the teal repositories.

Acceptance criteria

• CLAUDE.md is added to the repository.
• The file follows the structure agreed in Define a common CLAUDE.md structure for teal repositories nestdevs-tasks#121.
• Repository-specific guidance is included where relevant.