Return short entries from list tools #303

See #302. Lists identify, sort and filter; item_get returns details. Fastest gain: this alone shrinks task_list from 266,000 characters to a small fraction, without new parameters.

Work

• task_list: number, parent number, title, status, priority, assignee (name, owner label, reference), subtask counts, created and updated time. No description.
• item_search: memories keep their summary (it is the short form); tasks and pages return number, title and state, pages keep their excerpt since it explains the hit.
• proposal_get queue: identity, target, author, status and time; the payload only for a single proposal.
• Check the remaining list-shaped responses (relation_list, item_history, privacy_deletion_queue) and apply the same rule.
• Tool descriptions and system guide say that lists are short and item_get returns the full item.

Acceptance

• A test fixes the fields of each list entry, so details cannot creep back in unnoticed.
• The web app is unaffected (it uses the services, not the MCP shapes); verify.
• Tool list budget test passes; record the measured task_list size for a large fixture before and after.