Back to Search-quality baseline: symbol-attribute (Phase 1.6, v1.2.0 candidate)

An AI agent issuing `find async throws functions returning Result` gets top-10 results that don't constrain on async/throws/return-type. The agent then has to read those pages and hope they're relevant; for most of the 8-zero-P@5 queries above, none would be useful.

Mitigation in current state: the agent would need to issue more concrete queries (`Result<Success, Failure>` plus `async throws` separately and intersect mentally) rather than rely on cupertino to filter. This is feasible but inefficient.

The Phase 1.7 agent-end-to-end eval (`docs/design/search-quality-eval.md` §14.4) is where the practical impact of these attribute-query limitations gets measured end-to-end. Until that lands, this 25% baseline is the closest signal.