List Shared Data Conversation Turns

Return the user's conversation as turn-grouped, redacted records.

Pulls every message in the user's single conversation (capped at limit rows so a runaway transcript does not OOM the response), groups them into turns via :func:_group_turns, and returns each turn with its user message, agent reply, and the tool calls fired during the turn. Each tool call is redacted at the leaves: args is walked recursively and result is string-redacted, so a query like qb_query("...WHERE customer_name='John Smith'") does not surface the customer name even when the conversation is opened.

The consent gate is re-checked server-side, so a user revoking consent mid-investigation immediately starts returning 403.