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

`@MainActor`, `Sendable conformance`, `protocol type`, `Hashable conformance` — these all happen to align with token-presence:

- `MainActor` is also a Swift type name, indexed in `docs_fts.symbols` at weight 5.0
- `Sendable` is a Swift protocol name, same
- `Hashable` same
- `protocol` is a Swift keyword that appears in titles and content
- `actor` (in `actor type`) appears in titles for the 3 actor-defining pages but those pages don't dominate

So the win isn't the symbol-attribute mechanism working; it's a coincidence that the attribute name is also a token-rich symbol name. When the attribute name is a generic English word that doesn't surface as a symbol (`initializer`, `subscript`, `typealias`, `generic constraint`), the query fails completely.