Get Shared Project Chats

Get chat history for a shared project (read-only).

The anonymous share wire keeps only user and assistant prose, user attribution, and message timestamps. It removes thinking, instructions, retry and tool parts, run and provider fields, and private metadata. Assistant prose is not scanned for incidental parcel mentions because parsing free-form model text is unreliable and outside this restriction's scope.

Args: share: Validated ProjectShare from token share_service: ProjectShareService for fetching chat data

Returns: Prose-only chat history, or None if no chat exists