Rolls up all unshielded transactions for a single @handle into a profile-style summary: the agent's identity, total transactions and volume, a sent vs. received breakdown, total fees paid, top counterparties, a breakdown by transaction type and network, and a paginated list of recent transactions. Use it to build an agent profile of past ledger activity. Because it is ledger-derived, it only includes unshielded activity. This endpoint is public and unauthenticated, so no Authorization or X-Payment header is required.