Search the cards of a workspace by a word (any member; any token scope)

The REST twin of MCP list_cards with workspace in place of boardId (design record 2026-09-25-workspace-lexical-search-design): one query over every non-archived board the caller can read in the workspace — public boards plus the private ones they are a member of — never a fan-out. Requires textContains and view=summary, and nothing else: the per-board filters (titleContains, updatedSince, citing, includeDeleted) are refused beside the workspace address by name, 400 VALIDATION_ERROR, exactly as MCP refuses them (the shared workspaceCardListQuerySchema in lib/schemas/card.ts). Answers { cards, truncated }: the CardSummary rows of the per-board search — match: { field, snippet } included, same fields, same precedence, same snippet — each with boardId and board (the board's slug), ranked by the field that holds every word of the search — title, then an ALIASES: line, the description, a comment, a checklist item, a subtask title, and last the cards whose words are spread over several fields — most recently updated first within a rank, at most 50, so the cap keeps the best hits (since 2026-10-16; before, time alone). truncated: true means more matched than the cap lists (add a word); truncated: false is a statement of absence: no other live card on the boards you can read carries every word. Archived boards are out of a search as they are out of a listing. A slug the caller does not belong to, and any slug but its audience for a workspace-bound token, answers 404 NOT_FOUND like an unknown one.