claude@clouddev1
7ae1a0fde1
Adds the `Ranker` plug-in point ADR-0024 §ranker-layer specified. The grammar tree declares *what's valid*; the ranker decides *what's likely useful first*. Default `identity_ranker` preserves declaration order from the grammar. API: - `pub type Ranker = fn(Vec<Candidate>) -> Vec<Candidate>;` - `pub const fn identity_ranker(c) -> Vec<Candidate>` returns its input unchanged. - `candidates_at_cursor_with(input, cursor, cache, ranker)` applies a custom ranker; the default `candidates_at_cursor` delegates with `identity_ranker`. Three new tests cover identity preservation, custom reordering, and the empty-list-collapses-to-None edge. This is a future-work hook — no production caller passes a non-identity ranker yet. Hooks for frequency-based ranking, content-aware priors, or recency plug in here without touching the grammar declarations. Tests: 809 passing, 0 failing, 1 ignored. Clippy clean.