PR #1918 replaced _pick_seeds(terms=) with best_seed_by_term= from
_score_query. Update the #1900 German-stopword seed test to the new
single-traversal API and add the missing trailing newline in the
(manual, non-collected) query-scoring benchmark.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Add _score_query() producing combined ranking + per-term singleton winners
in a single graph traversal. _pick_seeds consumes precomputed winners
instead of rescoring each term via _score_nodes.
Behavior byte-identical to the legacy T+1 path. Supersedes the rescoring
loop from #1596 while preserving its per-term coverage guarantee; folds
in coverage scaling from #1724 and multiplicity penalty from #1832.
Orthogonal to the trigram prefilter from #1431.
Benchmark (full sweep in #1889):
1k-100k nodes, 1-10 terms: 1.43x-2.43x median speedup
Single-term: no regression (1.70x-1.89x improvement)
Traversals: T+1 -> 1 regardless of term count
Tests: 3221 passed, 3 skipped. Ruff clean. Graphify graph updated.
Refs #1889
