Why admission and ranking are separate

The central design choice is that scoring cannot decide whether a candidate matches. Local alignment is intentionally willing to abandon a weak prefix; using its best traceback as an admission oracle therefore loses valid long-gap subsequences and makes highlights disagree with filtering.

sparkles:fuzzy instead admits a term through an exact, bounded needle-deletion cursor DP. The canonical witness minimizes deletions, then the ending candidate position, then source-byte positions. The same witness owns the scoring window, filename containment, offsets, and highlight ranges. Smith–Waterman only orders already-admitted candidates. Long candidates use a direct witness score, retaining exact admission and positions.

This separation also shapes ownership. Text analysis preserves the original byte interval through normalization, expansion, composition, and malformed UTF-8. A worker borrows immutable query and corpus arenas and owns its scratch. The fuzzy package stays pure and allocation-free; the application can then add a clock, atomics, a persistent CPU pool, and disk history without weakening the compute kernel or hiding those lifetimes.