Retrieves all solar system designs associated with a specific project.

Business Context:
Projects typically have multiple design iterations as the solar system layout
is refined through engineering review, customer feedback, and optimization processes.

Design Types:

• Primary Design: The active design used for financing and installation
• Secondary Designs: Alternative layouts, revisions, or archived versions

Common Use Cases:

• Review design iteration history
• Compare different layout options
• Access equipment specifications for procurement
• Generate customer presentation materials
• Track design approval status

Response Information:

• Design specifications (size, production, shading analysis)
• Equipment details (modules, inverters, racking, storage)
• Design source and creation metadata
• Primary/secondary design status