In a multi-term query, a lone generic term that exactly equals a short leaf
label (`home` vs a `home()` action, `list` vs a `list()` function) received
the full exact-tier bonus and outscored nodes matching several of the query's
terms by ~10x, so `_pick_seeds`' gap cutoff discarded the genuinely relevant
candidates and `path`-style consumers of `scored[0]` had no backstop.
`_score_nodes` now scales the per-term exact/prefix tier contributions by the
squared fraction of query terms the node's label matches
(`tiered * (matched / n_terms) ** 2`). Squared because the exact tier is 10x
the prefix tier; label hits only (source-path hits score but don't count as
coverage, so a colliding leaf in the target's own directory can't win its
exact tier back via path fragments); query tokens deduped order-preserving so
a repeated word can't quadratically restore the collision. Single-term and
full-coverage queries are unchanged (coverage == 1), keeping identifier
exact-match dominance. Guarded against zero-term division.
Dropped the unrelated README badge changes from the PR; kept the scoring fix
and its two regression tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
