Pi-Client Configuration Request

[miyatakazuya]

Summary: Introduce a Configuration Request command (e.g., CameraRequest::CONFIG'). When the OBC client initializes, it sends the CONFIG` request to the server.

The camera-things server responds with a structured packet containing the current JSON configuration parameters:

• Image Width/Height
• Stride X/Y + UV
• Pixel format
• Header/Chunk Size

This will allow us to have one source of config on the Pi-side only, without the need to keep both ends consistent.